Magnetic coupling device

ABSTRACT

A magnetic device for magnetically coupling to a ferromagnetic body, comprises a housing having a central bore. A plurality of pole sectors arranged within an envelope of the central bore and forming a workpiece contact interface of the magnetic device, each of the plurality of pole sectors comprising a plurality of spaced-apart pole portions arranged at respective distances, wherein a recess of a plurality of recesses separates each pole portion of the plurality of pole portions, wherein a first sector forms a first pole of the magnetic device and a second sector forms a second pole of the magnetic device. A first permanent magnet. A second permanent being moveable relative to the first permanent magnet. And, an actuator operatively coupled to the at least one second permanent magnet to move the at least one second permanent magnet relative to the at least one first permanent magnet.

RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 17/476,380 filed Sep. 15, 2021, which is acontinuation application of U.S. patent application Ser. No. 16/964,005filed Jul. 22, 2020 which is a national stage application of PCTApplication No. PCT/US19/15541, filed Jan. 29, 2019, titled MAGNETICLIFTING DEVICE HAVING POLE SHOES WITH SPACED APART PROJECTIONS, docketMTI-0015-01-WO which claims the benefit of U.S. Provisional ApplicationNo. 62/623,407, filed Jan. 29, 2018, titled MAGNETIC LIFTING DEVICEHAVING POLE SHOES WITH SPACED APART PROJECTIONS, docket MTI-0015-01-US,the entire disclosures of which are expressly incorporated by referenceherein.

TECHNICAL FIELD

The present disclosure relates to magnetic devices. More specifically,the present disclosure relates to pole shoes for switchable magneticdevices.

BACKGROUND

A switchable magnetic device may be used to magnetically couple themagnetic device to one or more ferromagnetic bodies. A switchablemagnetic device may include one or more magnet(s) that is (are)rotatable relative to one or more stationary magnet(s), to generate andshunt a magnetic field. The switchable magnet device may be attached ina removable manner, via switching the magnet device between an “on”state and an “off” state, to a ferromagnetic body (e.g., work piece),such as for object lifting operations, material handling, materialholding, magnetically latching or coupling objects to one another, amongother applications.

SUMMARY

Embodiments of the present disclosure relate to pole shoes for aswitchable magnetic device. In embodiments, the pole shoes comprise aplurality of projections, which facilitate creating shallow magneticfields in a ferromagnetic workpiece to be moved with the magneticdevice, the shallow magnetic field having sufficient holding force tolift the coupled ferromagnetic workpiece and hold the ferromagneticworkpiece against shear forces during transport. As such, switchablemagnetic devices including the pole shoes may be used to de-stack thinmaterials. Example embodiments include the following.

In an exemplary embodiment of the present disclosure, a magnetic devicefor magnetically coupling to a ferromagnetic body, comprises: a housinghaving a central bore; a plurality of pole sectors arranged within anenvelope of the central bore and forming a workpiece contact interfaceof the magnetic device, each of the plurality of pole sectors comprisinga plurality of spaced-apart pole portions arranged at respectivedistances, wherein a recess of a plurality of recesses separates eachpole portion of the plurality of pole portions, wherein a first sectorof the plurality of sectors form a first pole of the magnetic device anda second sector of the plurality of sectors form a second pole of themagnetic device; at least one first permanent magnet supported by thehousing and having an active N-S pole pair; at least one secondpermanent magnet supported by the housing and having an active N-S polepair, the at least one second permanent magnet being moveable relativeto the first permanent magnet; and an actuator operatively coupled tothe at least one second permanent magnet to move the at least one secondpermanent magnet relative to the at least one first permanent magnet,wherein the magnetic device establishes a first magnetic circuit withthe at least one first permanent magnet and the at least one secondpermanent magnet through the plurality of pole sectors when the at leastone second permanent magnet is positioned by the actuator in a firstposition relative to the at least one first permanent magnet and asecond magnetic circuit with the first permanent magnet and the secondpermanent magnet when the second permanent magnet is positioned by theactuator in a second position relative to the at least one firstpermanent magnet.

In an example thereof, the at least one first permanent magnet comprisesa first platter supported by the housing, the first platter comprising afirst plurality of spaced-apart permanent magnet portions each having anorth pole side and a south pole side and a first plurality of poleportions interposed between adjacent permanent magnet portions of thefirst plurality of permanent magnet portions, wherein the first plattercomprises an equal number of permanent magnet portions and pole portionsand the first plurality of permanent magnets are arranged so that eachpole portion of the first plurality of pole portions is one of a northpole portion which is adjacent the north pole side of two permanentmagnet portions of the first plurality of permanent magnet portions anda south pole portion which is adjacent the south pole side of twopermanent magnet portions of the first plurality of permanent magnetportions; and wherein the at least one second permanent magnet comprisesa second platter supported by the housing, the second platter comprisinga second plurality of spaced-apart permanent magnet portions each havinga north pole side and a south pole side and a second plurality of poleportions interposed between adjacent permanent magnet portions of thesecond plurality of permanent magnet portions, wherein the secondplatter comprises an equal number of permanent magnet portions and poleportions and the second plurality of permanent magnets are arranged sothat each pole portion of the first plurality of pole portions is one ofa north pole portion which is adjacent the north pole side of twopermanent magnet portions of the second plurality of permanent magnetportions and a south pole portion which is adjacent the south pole sideof two permanent magnet portions of the second plurality of permanentmagnet portions, the second platter including a rotation engagementportion.

In another example thereof, the actuator rotates the at least one secondpermanent magnet relative to the at least one first permanent magnet.

In even another example thereof, the actuator is one of a rotaryactuator and a linear actuator.

In even another example thereof, the actuator linearly translates the atleast one second permanent magnet relative to the at least one firstpermanent magnet.

In even another example thereof, the at least one second permanentmagnet is housed in a second housing received in the housing, the secondhousing being rotatable by the actuator to rotate the at least onesecond permanent magnet.

In another exemplary embodiment of the present disclosure, a magneticdevice for magnetically coupling to a ferromagnetic body, comprises: ahousing having a central bore; a plurality of pole sectors arrangedwithin an envelope of the central bore and forming a workpiece contactinterface of the magnetic device, each of the plurality of pole sectorscomprising a plurality of spaced-apart pole portions arranged atrespective distances, wherein a recess of a plurality of recessesseparates each pole portion of the plurality of pole portions, wherein afirst sector of the plurality of sectors form a first pole of themagnetic device and a second sector of the plurality of sectors form asecond pole of the magnetic device; at least one first permanent magnetsupported by the housing and having an active N-S pole pair; and anactuator operatively coupled to the at least one first permanent magnetto move the at least one first permanent magnet relative to a base ofthe housing, wherein the magnetic device establishes a first magneticcircuit through the plurality of pole sectors when the at least onefirst permanent magnet is positioned by the actuator in a first positionrelative to the base of the housing and a second magnetic circuitsubstantially within the housing when the at least one first permanentmagnet is positioned by the actuator in a second position relative tothe base of the housing.

In an example thereof, the first magnetic circuit passes through thefirst sector and the second sector to couple the ferromagnetic body tothe magnetic device and the second magnetic circuit is substantiallyconfined within at least a portion of the housing.

In another example thereof, each recess of the plurality of recesses issized to prevent the ferromagnetic body from entering the respectiverecess.

In even another example thereof, each of the plurality of recesses has arespective profile extending between the adjacent pole portions, therespective profile having a continuous slope.

In even another example thereof, at least one of the plurality ofrecesses has a depth substantially equal to a thickness of theferromagnetic body to be coupled to the magnetic device.

In even another example thereof, each of the recesses has a depthsubstantially equal to a thickness of the ferromagnetic body to becoupled to the magnetic device.

In even another example thereof, at least one of the recesses has awidth substantially equal to a thickness of the ferromagnetic body to becoupled to the magnetic device.

In even another example thereof, each of the recesses has a widthsubstantially equal to a thickness of the ferromagnetic body to becoupled to the magnetic device.

In even another example thereof, at least one of the recesses has awidth substantially equal to a depth of the at least one recess.

In even another example thereof, each of the plurality of pole sectorsis a single unitary pole sector.

In even another example thereof, each of the plurality of pole sectorsextend below the housing such that the housing is spaced apart from theferromagnetic body when the workpiece contact interfaces of the firstsector and the second sector contact the ferromagnetic body.

In even another example thereof, further comprising a compressiblemember arranged between each of the plurality of pole portions.

In even another example thereof, the workpiece contact interface forms anon-linear workpiece contact interface.

In even another example thereof, the workpiece contact interface forms alinear workpiece contact interface.

In even another example thereof, the actuator is one of a hydraulicactuator, a pneumatic actuator, and an electrical actuator.

In even another example thereof, each of the plurality of pole sectorscarries a compressible component positioned to be in contact with theferromagnetic body when the ferromagnetic body is coupled to themagnetic device.

In even another example thereof, the magnetic coupling device is carriedby at least one selected from the group of: mechanical gantry, cranehoist, stationary fixture, and a robotic fixture.

In another exemplary embodiment of the present disclosure, a method ofattaching a magnetic device to a ferromagnetic body, the magnetic deviceconfigured to establish a first magnetic circuit and a second magneticcircuit and the magnetic device comprising a housing having a centralbore, at least one first permanent magnet supported by the housing andhaving an active N-S pole pair, at least one second permanent magnetsupported by the housing and having an active N-S pole pair, the atleast one second permanent magnet being moveable relative to the firstpermanent magnet, and a plurality of pole sectors arranged within anenvelope of the central bore and forming a workpiece contact interfaceof the magnetic device, the method comprising the steps of: contactingthe ferromagnetic body with a first sector of the plurality of polesectors, the first sector including a plurality of spaced-apart poleportions arranged at respective distances that collectively form thecontact interface of the first sector; contacting the ferromagnetic bodywith a second sector of the plurality of sectors, the second sectorincluding a plurality of spaced-apart pole portions that collectivelyform the contact interface of the second sector; and

transitioning the magnetic device from an off-state to an on-state.

In an example thereof, the first magnetic circuit substantially passesthrough the first sector and the second sector to couple theferromagnetic body to the magnetic device and the second magneticcircuit is substantially confined within at least a portion of thehousing.

In another exemplary embodiment of the present disclosure, a magneticcoupling device for magnetic coupling to a ferromagnetic workpiece,comprises: a housing having a vertical axis extending between an upperportion of the housing and a lower portion of the housing; one or moreferromagnetic pieces arranged at or near an upper portion of thehousing; a pole plate support by the housing, the pole plate comprisinga plurality of projections that collectively form a workpiece contactinterface for the ferromagnetic workpiece; a magnetic platter supportedby the housing, the magnetic platter comprising more than one permanentmagnet portions and a plurality of pole portions, wherein each permanentmagnet portion of the one or more permanent magnet portions is arrangedadjacent to two pole portions of the plurality of pole portions so thatpole portions of the plurality of pole portions is one of: a north poleportion that is adjacent to a north pole side of at least one permanentmagnet portion of the one or more permanent magnet portions and a southpole portion that is adjacent to a south pole side of at least onepermanent magnet portion of the one or more permanent magnet portions;and wherein the magnetic platter is linearly translatable within thehousing along the vertical axis to at least each of a first state and asecond state, the magnetic platter being arranged adjacent to the one ormore ferromagnetic pieces such that the magnetic coupling deviceestablishes a first magnetic circuit through the one or moreferromagnetic pieces and provides a first magnetic field at theworkpiece contact interface of the magnetic coupling device when themagnetic platter is in the first state and the magnetic platter beingarranged spaced apart from the one or more ferromagnetic pieces suchthat the magnetic coupling device provides a second magnetic field atthe workpiece contact interface when the magnetic platter is in thesecond state, the second magnetic field being a non-zero magnetic fieldstrength.

Other aspects and optional and/or preferred embodiments will becomeapparent from the following description provided below with reference tothe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a front representative view of an exemplaryswitchable magnetic device in an off state.

FIG. 1B illustrates a front representative view of the exemplaryswitchable magnetic device depicted in FIG. 1A in an on state.

FIG. 1C illustrates a side representative view the exemplary switchablemagnetic device depicted in FIGS. 1A and 1B.

FIG. 2A illustrates a side representative view of another exemplaryswitchable magnetic device.

FIG. 2B illustrates a top representative view of the exemplaryswitchable magnet depicted in FIG. 2A.

FIG. 3 illustrates a schematic exploded view of an exemplary switchablemagnetic device with pole shoes.

FIG. 4 illustrates an isometric view of the switchable magnetic devicedepicted in FIG. 3 in an assembled state.

FIG. 5A illustrates a front sectional view of the switchable magneticdevice depicted in FIGS. 3 and 4 and the magnetic circuit created whenthe device is in an “off” state.

FIG. 5B illustrates a front sectional view of the switchable magneticdevice depicted in FIGS. 3 and 4 and the magnetic circuit created whenthe device is in an “on” state.

FIG. 6 illustrates a side view of a portion of an exemplary pole shoe.

FIG. 7A illustrates a side view of a portion of another exemplary poleshoe and FIG. 7B illustrates a detail view of a portion of the exemplarypole shoe depicted in FIG. 7A.

FIG. 8 illustrates a side view of a portion of another exemplary poleshoe.

FIGS. 9A-9B illustrates another exemplary pole plate.

FIGS. 10A-10B illustrates another exemplary pole plate.

FIG. 11A illustrates a front view of another exemplary switchablemagnetic device.

FIG. 11B illustrates a side view of the switchable magnetic devicedepicted in FIG. 11A.

FIG. 12 illustrates a processing sequence of a method of use of anexemplary switchable magnetic device with pole shoes.

FIG. 13 illustrates a robotic system including a switchable magneticdevice.

FIG. 14 illustrates a diagrammatical view of an exemplary magneticcoupling device having an upper assembly and a lower assembly, eachincluding a plurality of permanent magnets and pole portions arranged ina linear array, the magnetic coupling device being in an on state.

FIG. 15 illustrates the magnetic coupling device of FIG. 14 in an offstate.

FIG. 16 illustrates a perspective view of the two instances of anexemplary platter having a plurality of permanent magnets and poleportions;

FIG. 17 illustrates an exploded, perspective view of the platter of FIG.16 ;

FIG. 18 illustrates a top, assembled view of the platter of FIG. 16 ;

FIG. 19 illustrates an exploded, perspective view of another exemplarymagnetic coupling device with pole shoes;

FIG. 20 illustrates a perspective, assembled view of the magneticcoupling device of FIG. 19 ;

FIG. 21 illustrates a bottom, assembled view of the magnetic couplingdevice of FIG. 19 ;

FIG. 22 illustrates a cross-sectional view of the magnetic couplingdevice of FIG. 19 ;

FIG. 23 illustrates a cross-sectional view of another magnetic couplingdevice with pole portions in an exemplary on state coupled to aferromagnetic workpiece;

FIG. 24 illustrates a cross-sectional view of the magnetic couplingdevice depicted in FIG. 23 in an exemplary off state positioned above astack of a plurality of ferromagnetic workpieces;

FIG. 25 illustrates a bottom view of the magnetic coupling device ofFIG. 23 ;

FIG. 26 illustrates a cross-sectional view of the magnetic couplingdevice of FIG. 23 with pole shoes in an exemplary on state coupled to aferromagnetic workpiece; and

FIG. 27 illustrates a cross-sectional view of the magnetic couplingdevice depicted in FIG. 26 in an exemplary off state positioned above astack of a plurality of ferromagnetic workpieces.

FIG. 28A illustrates a side-sectional view of another exemplary magneticcoupling device in an exemplary first, off state positioned on a stackof ferromagnetic workpieces.

FIG. 28B illustrates a front sectional view of the magnetic couplingdevice of FIG. 28A.

FIG. 29 illustrates a front sectional view of the magnetic couplingdevice of FIGS. 28A-28B in a second, on state.

FIG. 30 illustrates a front sectional view of the magnetic couplingdevice of FIGS. 28A-28B in a third, on state.

FIG. 31 illustrates an exploded view of the magnetic coupling device ofFIGS. 28A-28B.

FIGS. 32A-32B illustrate a top sectional view of the magnetic couplingdevice of FIGS. 28A-28B in different positions on a ferromagneticworkpiece.

FIG. 33 illustrates a processing sequence of a method of use of anexemplary switchable magnetic device with pole portions.

While the disclosed subject matter is amenable to various modificationsand alternative forms, specific embodiments have been shown by way ofexample in the drawings and are described in detail below. Theintention, however, is not to limit the disclosure to the particularembodiments described. On the contrary, the disclosure is intended tocover all modifications, equivalents, and alternatives falling withinthe scope of the disclosure.

DETAILED DESCRIPTION OF THE DRAWINGS

Embodiments provided herein relate to switchable magnetic devices.Exemplary switchable magnetic devices are disclosed in U.S. Pat. No.7,012,495, titled SWITCHABLE PERMANENT MAGNETIC DEVICE; U.S. Pat. No.7,161,451, titled MODULAR PERMANENT MAGNET CHUCK; U.S. Pat. No.8,878,639, titled MAGNET ARRAYS, U.S. Provisional Patent Application No.62/248,804, filed Oct. 30, 2015, titled MAGNETIC COUPLING DEVICE WITH AROTARY ACTUATION SYSTEM, docket MTI-0007-01-US-E; and U.S. ProvisionalPatent Application No. 62/252,435, filed Nov. 07, 2015, titled MAGNETICCOUPLING DEVICE WITH A LINEAR ACTUATION SYSTEM, docket MTI-0006-01-US-E,the entire disclosures of which are expressly incorporated by referenceherein.

The illustrated examples herein provide exemplary switchable magneticdevices having a first permanent magnet and a second permanent magnetmovable relative to the first permanent magnet, similar to the exemplaryswitchable magnetic devices of the '495 Patent which is expresslyincorporated by reference herein. The permanent magnets may each becylindrical unitary di-pole body of a single type of rare earth magnetmaterial, such as NdFeB or SmCo. Additional types of switchable magneticdevices may be implemented. Each type of switchable magnetic deviceincludes at least a first permanent magnet that is movable relative to asecond permanent magnet. Further, exemplary switchable magnetic devicesmay include a first plurality of permanent magnets movable relative to asecond plurality of permanent magnets. Additionally, exemplaryswitchable magnetic devices may include at least a first permanentmagnet positioned within a first housing which acts as a pole extensionof the at least a first permanent magnet, the first housing beingmovable relative to a second housing having at least a second permanentmagnet positioned within the second housing, the second housing acts asa pole extension of the at least a second permanent magnet.

Further, exemplary switchable magnetic devices may include a firstplurality of permanent magnets movable relative to a second plurality ofpermanent magnets. Two examples are provided in FIGS. 15-18 . Exemplarysystems are disclosed in U.S. Provisional Patent Application No.62/248,804, filed Oct. 30, 2015, titled MAGNETIC COUPLING DEVICE WITH AROTARY ACTUATION SYSTEM, docket MTI-0007-01-US-E; and U.S. ProvisionalPatent Application No. 62/252,435, filed Nov. 7, 2015, titled MAGNETICCOUPLING DEVICE WITH A LINEAR ACTUATION SYSTEM, docket MTI-0006-01-US-E,and U.S. Pat. No. 7,161,451, the entire disclosures of which areexpressly incorporated by reference herein.

Referring to FIGS. 1A-1C, an exemplary switchable magnetic device 10 isrepresented. Switchable magnetic device 10 includes an upper permanentmagnet 12 and a lower permanent magnet 14 positioned in a stackedrelationship in a housing 28. Permanent magnet 12 comprises a south-poleportion (S-pole portion) 18 and a north-pole portion (N-pole portion)20. Similarly, permanent magnet 14 comprises a N-pole portion 22 and aS-pole portion 24. Housing 28 may include multiple components assembledtogether to form a housing. Further, housing 28 may include features tomaintain permanent magnet 12 spaced apart from permanent magnet 14 or toincorporate spacers, such as spacer 13 in the illustrated embodiment,which maintains permanent magnet 12 is spaced apart relation relative topermanent magnet 14. Spacer 13 is made of a non-magnetic material toisolate permanent magnet 12 from permanent magnet 14.

Pole shoes 16′, 16″ are coupled housing 28. Pole shoes 16′, 16″ are madeof a ferromagnetic material and are magnetically coupled to magnets 12,14 through portions of housing 28. A lower portion of each of pole shoes16′, 16″ include a workpiece contact interface 17′, 17″ which may bebrought into contact with a workpiece 27, illustratively a top sheet 27′of ferromagnetic material of a stack of sheets 27′, 27″, and 27″ of theferromagnetic material. Workpiece contact interfaces 17′, 17″ of poleshoes 16′, 16″ cooperate with magnets 12, 14 through pole shoes 16′, 16″and housing 28 to form first and second poles of the magnets 12, 14. Inone example, a single unitary pole shoes forms each of the pole shoes16′, 16″. In another example, a plurality of pole shoes form each of theunitary pole shoes 16′, 16″.

In embodiments, permanent magnet 14 is fixed relative to housing 28 andpermanent magnet 12 is movable within housing 28 relative to permanentmagnet 14 in order to alter an alignment of the magnet portions 18, 20of the permanent magnet 12 relative to the magnet portions 22, 24 ofpermanent magnet 14. In the illustrated embodiment, permanent magnet 12is rotatable relative to permanent magnet 14.

Switchable magnetic device 10 based on the configuration of permanentmagnets 12, 14 establishes two different magnetic circuits. Inparticular, switchable magnetic device 10 establishes a first magneticcircuit referred to as on-state of switchable magnetic device 10 whenpermanent magnet 12 is rotated such that the S-pole portion 18 ofpermanent magnet 12 is adjacent the S-pole portion 24 of permanentmagnet 14 and the N-pole portion 20 of permanent magnet 12 is adjacentthe N-pole portion 22 of permanent magnet 14 (shown in FIG. 1B). In theon-state, one or more workpieces 27 being made of a ferromagneticmaterial, such as iron or steel, are held by the switchable magneticdevice 10 due to a completion of the magnetic circuit from the alignedN-pole portions 20, 22 of the upper and lower magnets 12, 14,respectively, through the housing 28 and pole shoe 16′, through one ormore workpiece sheets 27, through pole shoe 16″ and housing 28, and tothe aligned S-pole portions 18, 24 of the upper and lower magnets 12,14, respectively. The workpiece contact interface 17′ of pole shoe 16′functions as a North pole of switchable magnetic device 10. Theworkpiece contact interface 17″ of pole shoe 16″ functions as a Southpole of switchable magnetic device 10.

As explained in more detail herein the size and shape of pole shoes 16′,16″ result in the first magnetic circuit being substantially confined toworkpiece sheet 27′ of workpiece sheets 27 and of sufficient holdingforce to vertically lift workpiece sheet 27′ in direction 33 relative tothe remainder of workpiece sheets 27. Thus, switchable magnetic device10 may function to de-stack workpiece sheets 27. Of course, in someembodiments, a portion of the magnetic flux provided to workpiece sheets27 by switchable magnet device 10 may enter lower sheet 27″ of workpiecesheets 27, but not to a level that results in lower sheet 27″ beinglifted by switchable magnetic device 10 along with workpiece sheet 27′.Thus, as used herein, the first magnetic circuit being substantiallyconfined to workpiece sheet 27′ of workpiece sheets 27 means that theamount, if any, of the magnetic flux from switchable magnetic liftingdevice 10 entering lower sheet 27″ is below a level that would result inthe lower sheet 27″ being vertically lifted in direction 33 byswitchable magnetic lifting device 10 along with workpiece sheet 27′.

Switchable magnetic device 10 establishes a second magnetic circuitreferred to as off-state of switchable magnetic device 10 when permanentmagnet 12 is rotated such that the S-pole portion 18 of permanent magnet12 is adjacent the N-pole portion 22 of permanent magnet 14 and theN-pole portion 20 of permanent magnet 12 is adjacent the S-pole portion24 of permanent magnet 14 (shown in FIG. 1A). In the off-state, one ormore workpieces 27 being made from a ferromagnetic material, such asiron or steel, are not held by the switchable magnetic device 10 due toa completion of a magnetic circuit between switchable magnetic device 10and the workpiece sheets 27 because the aligned S-pole portion 18 ofmagnet 12 and the N-pole portion 22 of magnet 14 and the aligned N-poleportion 20 of magnet 12 and the S-pole portion 24 of magnet 14. In otherwords, the alignment of the magnets 12, 14 results in a shunted magneticcircuit substantially within the switchable magnetic device 10 causingthe external magnetic field to collapse. In one example, at least 96%percent of the magnetic flux produced by magnets 12, 14 is retained inswitchable magnetic device 10 when switchable magnetic device 10 is inthe off state. In another example, at least 99% of the magnetic fluxproduced by magnets 12, 14 is retained at the workpiece contactinterfaces 17′, 17″.

Returning to FIG. 1A, switchable magnetic device 10 includes anengagement portion 30 and an actuator 32. Engagement portion 30 couplesactuator 32 to permanent magnet 12 such that actuator 32 may reorientpermanent magnet 12 relative to permanent magnet 14. Exemplaryengagement portions 30 include one or recesses in permanent magnet 12and/or a housing supporting permanent magnet 12, one or more protrusionsextending from permanent magnet 12 and/or a housing supporting permanentmagnet 12, and/or one or more linkages or gear systems coupled topermanent magnet 12 and/or a housing supporting permanent magnet 12.Exemplary actuators include rotary actuators and linear actuators, eachof which through engagement portion 30 can impart a rotation topermanent magnet 12.

Exemplary engagement portions and actuators are disclosed in U.S. Pat.No. 7,012,495, titled SWITCHABLE PERMANENT MAGNETIC DEVICE; U.S. Pat.No. 7,161,451, titled MODULAR PERMANENT MAGNET CHUCK; U.S. Pat. No.8,878,639, titled MAGNET ARRAYS, U.S. Provisional Patent Application No.62/248,804, filed Oct. 30, 2015, titled MAGNETIC COUPLING DEVICE WITH AROTARY ACTUATION SYSTEM, docket MTI-0007-01-US-E; and U.S. ProvisionalPatent Application No. 62/252,435, filed Nov. 7, 2015, titled MAGNETICCOUPLING DEVICE WITH A LINEAR ACTUATION SYSTEM, docket MTI-0006-01-US-E,the entire disclosures of which are herein expressly incorporated byreference.

In embodiments, actuator 32 is coupled to an electronic, pneumatic, orhydraulic controller 34 which controls the operation of actuator 32 andhence the alignment of permanent magnet 12 relative to permanent magnet14 through engagement portion 30. As illustrated in FIG. 1A, controller34 includes a processor 36 with an associated computer readable medium,illustratively memory 38. Memory 38 includes a magnetic coupler statelogic 40 which when executed by processor 36 causes electroniccontroller 34 to instruct rotary actuator 32 to move permanent magnet 12so that switchable magnetic device 10 is placed in one of the on-stateand the off-state. The term “logic” as used herein includes softwareand/or firmware executing on one or more programmable processors,application-specific integrated circuits, field-programmable gatearrays, digital signal processors, hardwired logic, or combinationsthereof. Therefore, in accordance with the embodiments, various logicmay be implemented in any appropriate fashion and would remain inaccordance with the embodiments herein disclosed. A non-transitorymachine-readable medium comprising logic can additionally be consideredto be embodied within any tangible form of a computer-readable carrier,such as solid-state memory, magnetic disk, and optical disk containingan appropriate set of computer instructions and data structures thatwould cause a processor to carry out the techniques described herein.This disclosure contemplates other embodiments in which the magneticcoupler state logic is not microprocessor-based, but rather isconfigured to control operation of switchable magnetic device 10 basedon one or more sets of hardwired instructions and/or softwareinstructions stored in memory 38. Further, controller 34 may becontained within a single device or be a plurality of devices networkedtogether to provide the functionality described herein.

In embodiments, the electronic controller 34 changes the state ofswitchable magnetic device 10 in response to an input signal receivedfrom an input device 42. Exemplary input devices include switches,buttons, touch screens, microphones, detectors, controllers, and otherdevices whereby an operator may provide one of a tactile, audio, orvisual input command. For example, in one embodiment, switchablemagnetic device 10 is coupled to an end of arm of a robotic arm andinput device 42 is a network interface over which controller 34 receivesinstructions from a robot controller on when to place switchablemagnetic device in one of an on-state and an off-state. Exemplarynetwork interfaces include a wired network connection and an antenna fora wireless network connection. While the embodiments discussed aboverelate to electronic, pneumatic, or hydraulic actuation, in alternativeembodiments, the switchable magnetic device 10 may be actuated manually.Exemplary manual actuators include handles, knobs, and other devicesactuatable by a human operator.

Referring to FIG. 1C, pole shoes 16′, 16″ (pole shoe 16″ illustrated)includes a plurality of projections 44 and recesses 46 separating theprojections 44. In embodiments, the pole shoes 16′, 16″ may include anynumber of recesses 46 and any number of projections 44 arranged on eachside of the recesses 46. The plurality of recesses 46 are sized toprevent the workpieces 27 from entering the respective recesses 46. Assuch, an interface 17 for a workpiece 27 is formed collectively by theprojections 44. In one example, each of pole shoes 16′, 16″ has a firstnumber of projections 44 and a second number of recesses 46 interposedbetween the first number of projections, the second number being atleast two. In a variation thereof, the second number is at least three.In a further variation thereof, the second number is at least five.

As a result of the projections 44 and recesses 46 the switchablemagnetic device 10 produces an external magnetic field 50 (shown in FIG.1B) that is more concentrated closer to interface 17 than an externalmagnetic field that would be produced by the same magnetic device 10 ifthe pole shoes 16′, 16″ didn't include the projections 44 and recesses46. More specifically, as illustrated in FIG. 1B, the external magneticfield 50 substantially passes through the first workpiece 27′ whilesubstantially none of the magnetic field 50 passes through either thesecond workpiece 27″ and/or the third workpiece 27′″. While the magneticfield 50 illustrates that substantially none of the magnetic field 50passes through the second workpiece 27″, some of the magnetic field 50may leak into the second workpiece 27″. Conversely, if the pole shoes16′, 16″ didn't include the projections 44 and recesses 46, then theexternal magnetic field 50 would likely penetrate deeper into the stackof workpiece sheets 27 into second workpiece sheet 27″ and/or the thirdworkpiece sheet 27′″. This would lower the chance that the upperworkpiece sheet 27′ could be de-stacked from the second workpiece sheet27″.

Tables 1 and 2 illustrate the average breakaway force of switchablemagnetic devices on workpieces having different thicknesses.Specifically, Table 1 illustrates switchable magnetic devices having afirst type of magnet, wherein a first switchable magnetic device of theswitchable magnetic devices having a first type of magnet has pole shoesthat don't have projections 44 and a second switchable magnetic device10 of the switchable magnetic devices having a first type of magnet haspole shoes 16′, 16″ that do have projections 44. Table 2 illustratesswitchable magnetic devices having a second type of magnet, wherein afirst switchable magnetic device of the switchable magnetic deviceshaving a second type of magnet has pole shoes that don't haveprojections 44 and a second switchable magnetic device 10 of theswitchable magnetic devices having a second type of magnet has poleshoes 16′, 16″ that do have projections 44.

TABLE 1 Average breakaway force of magnetic devices on workpieces havingdifferent thicknesses, wherein the magnetic devices have a first type ofmagnet Thickness Magnetic device Magnetic device of having pole shoeshaving pole shoes Workpiece without projections with projections (mm)(Kg) (Kg) 0.5 9.37 11.47 1.0 26.30 27.80 2.0 47.80 40.87 3.0 62.73 44.774.0 63.87 45.57 5.0 64.77 46.73 6.0 65.73 47.63 10.0 66.23 48.47

TABLE 1 Average breakaway force for magnetic devices on workpieceshaving different thicknesses, wherein the magnetic devices have a secondtype of magnet Thickness Magnetic device Magnetic device of having poleshoes having pole shoes Workpiece without projections with projections(mm) (Kg) (Kg) 0.5 7.87 9.33 1.0 22.67 24.50 2.0 43.63 37.10 3.0 56.8340.77 4.0 57.37 41.37 5.0 57.97 41.77 6.0 58.40 42.13 10.0 58.77 42.40

As shown in the data, the switchable magnetic device 10 having poleshoes 16′, 16″ with projections 44 has a higher average breakaway forceon thinner workpieces than the switchable magnetic device having poleshoes without projections. Moreover, as the thickness of the workpieceincreases, the switchable magnetic device 10 having pole shoes 16′, 16″with projections 44 has a lower overall average breakaway force.

As a result of the magnetic field 50 being concentrated near theinterface 17 of the pole shoes 16′, 16″, a switchable magnetic device 10including the pole shoes 16′, 16″ with projections 44 and recesses 46provides better de-stacking capabilities compared to the same switchablemagnetic device 10 that would include pole shoes without the projectionsand recesses. For example, the switchable magnetic device 10 includingthe pole shoes 16′, 16″ having the projections 44 and recesses 46 may bebetter able to de-stack thin sheet metal (e.g., 0.5 mm sheet metal, 1 mmsheet metal, 2 mm sheet metal, and/or the like) than the same switchablemagnetic device 10 that had pole shoes that didn't include theprojections 44 and recesses 46.

In addition, the dimensions of the projections 44 and recesses 46 may befurther configured to produce varying strengths of magnetic fields nearthe interface 44. That is, additional concentration of the magneticfield 50 near the interface 17 of pole shoes 16′, 16″ may be achieved bylengthening pole shoes 16′, 16″ relative to housing 28 and hencerelative to magnets 12, 14. In embodiments, the upper and lower magnets12, 14 and housing 28, which serves as a pole extension piece formagnets 12, 14, may have an outer envelope that is defined by a height52 (see FIG. 1B) of housing 28, a width 54 (see FIG. 1B) of housing 28,which extends on each side of a centerline 55 of switchable magneticdevice 10, and a length 58 of (see FIG. 1C) of housing 28. As shown inFIG. 1B, pole shoe 16′ is arranged on one side of the centerline 55 ofswitchable magnetic device 10 and the pole shoe 16″ is arranged on anopposite side of the centerline 55 of switchable magnetic device 10. Inone example, the pole shoes 16′, 16″ extend beyond at least one of theheight 52, the width 54, and/or the length 58 of the envelope of housing28. In the illustrated embodiment, the pole shoes 16′, 16″ extend beyondthe height 52 (lower than housing 28, see FIG. 1B), width 54 (positionedoutboard of housing 28, see FIG. 1B), and length 58 (both forward of andrearward of housing 28, see FIG. 1C) of the envelope of housing 28.

In some embodiments, the distance 60 (shown in FIG. 1A) between thebottom of housing 28 and interface 17 of pole shoes 16′, 16″ and/orlength 62 of pole shoes 16′, 16″ (shown in FIG. 1C) may be varied toproduce different magnetic field strengths near interface 17, asdiscussed below in relation to FIGS. 11A, 11B.

While the embodiments disclosed in relation to FIGS. 1A-1C included oneupper magnet 12 and one lower magnet 14, in alternative embodiments, theswitchable magnetic device 10 may comprise more than one upper magnet 12and more than one lower magnet 14. One such example is shown in FIGS. 2Aand 2B.

FIG. 2A is a side representative view of another exemplary switchablemagnetic device 10′ and FIG. 2B is a top representative view ofswitchable magnet 10′. As illustrated in FIGS. 2A and 2B, switchablemagnetic device 10′ includes a plurality of upper permanent magnets 12and a plurality of lower permanent magnets 14, illustratively threeupper magnets 12′, 12″, 12′″ and three lower magnets 14′, 14″, 14′″.Upper and lower magnets 12′, 14′ form a first set of magnets 56′. Upperand lower magnets 12″, 14″ form a second set of magnets 56″. Upper andlower magnets 12′″, 14′″ form a third set of magnets 56′″. The sets ofmagnets 56′, 56″, 56′″ are separated from one another.

Each set of magnets 56′, 56″, 56′″ produces a magnetic field thatpropagates from respective N-poles of the sets of magnets 56′, 56″, 56′″through the pole shoes 16′, 16″ to respective south poles of the sets ofmagnets 56′, 56″, 56′″. In embodiments where magnetic device 10′ is inan on-state, the magnetic field extends through workpiece 27′ whenworkpiece 27′ is in contact with interface 17 of pole shoes 16′, 16″.When magnetic device 10′ is in an off-state, the magnetic field issubstantially confined internally to magnetic device 10′. While poleshoes 16′, 16″ are illustrated as spanning the sets of magnets 56′, 56″,56′″ in alternative embodiments, the switchable magnetic device 10′ mayinclude multiple pole shoes 16′, 16″ that collectively span the sets ofmagnets 56′, 56″, 56′″. Additionally or alternatively, the switchablemagnetic device 10′ may include 2, 4, 5, etc. sets of magnets 56′, 56″,56′″.

While the switchable magnetic device 10 is described as being in astacked relationship, other switchable magnetic devices that don't havemagnets in a stacked relationship may be used in conjunction with thepole shoes 16′, 16″. Exemplary non-stacked switchable magnetic devicesare described in U.S. patent application Ser. No. 15/803,753, filed Nov.4, 2017, titled MAGNET ARRAYS, the entire disclosure of which isexpressly incorporated herein by reference.

Additional details of an exemplary switchable magnetic device 100 arediscussed next in relation to FIGS. 3 and 4 . In particular, FIG. 3 is aschematic exploded view of an exemplary switchable magnetic device 100with ferromagnetic pole shoes 102′, 102″ and FIG. 4 is an isometric viewof the switchable magnetic device 100 in an assembled state. Additionaldetails regarding magnetic device 100 are provided in U.S. ProvisionalApplication Ser. No. 62/517,057, filed Jun. 8, 2017, titledELECTROMAGNET-SWITCHABLE PERMANENT MAGNET DEVICE, the entire disclosureof which is expressly incorporated by reference herein.

During the discussion of FIGS. 3 and 4 , reference will also be made toFIG. 5A which is a front sectional view of switchable magnetic device100 and the magnetic circuit created when the device is in a firstconfiguration, i.e., the off-state. Additionally, reference also be madeto FIG. 5B which is a front sectional view of the switchable magneticdevice 100 when the magnetic device 100 is in a second configuration,i.e., the on-state.

Magnetic device 100 may have a plurality of configurations that resultin establishing different magnetic circuits. For example, switching themagnetic device 100 from a second configuration (shown in FIG. 3 andFIG. 5A), wherein the magnetic device 100 establishes a second magneticcircuit, to a first configuration (shown in FIG. 5B), wherein themagnetic device 100 establishes a first magnet circuit, may couple aferromagnetic body to the magnetic device 100 via the pole shoes 102′,102″, as explained below.

Magnetic device 100 comprises a central housing 104. The central housing104 includes two, ferromagnetic (e.g., steel) housing components 106,108, which may be joined by fasteners (not shown). The housingcomponents 106, 108 may additionally or alternatively be joined usingother methods and materials (e.g., epoxies, locating features(projections, indentations, chamfers, molded keyways, and/or the like),etc.). Housing component 106 may be referred to herein as the upperhousing component 106 and housing component 108 may be referred toherein as the lower housing component 108. Further, pole shoes 102′,102″ may be coupled to housing 104 with fasteners (not shown).

In embodiments, housing components 106, 108 may be a rectangularparallelepiped block of low reluctance ferromagnetic material. Acylindrical cavity 110 may extend through upper housing component 106and a cylindrical cavity 112 may extend through lower housing component108. Cylindrical cavities 110, 112 may be perpendicular to top faces114, 116 of the respective housing components 106, 108. Cylindricalcavity 110 may be referred to herein as the upper cylindrical cavity 110and cylindrical cavity 112 may be referred to herein as the lowercylindrical cavity 112. In embodiments, cylindrical cavities 110, 112may respectively receive magnets 118, 120. Magnet 118 may be referred toherein as the upper magnet 118 and magnet 120 may be referred to hereinas the lower magnet 120.

Upper housing component 106 has two sidewalls 124′, 124″ and lowerhousing component 108 has two sidewalls 126′, 126″. In embodiments,sidewalls 124′, 124″ of upper housing component 106 and sidewalls 126′,126″ of lower housing component 108 may have a thickness that containsthe magnetic field generated by magnets 118, 120 within housingcomponents 106, 108 when magnetic device 100 is in the firstconfiguration (shown in FIG. 5A).

In embodiments, upper magnet 118 has a N-S axis 128 and lower magnet 120has a N-S axis 130. Magnets 118, 120 may be NdFeB magnets and the activemagnetic mass and magnetic properties of magnets 118, 120 may be equaland/or equal within achievable manufacturing tolerances and permanentmagnet magnetization technologies.

In embodiments, lower magnet 120 is received and fixed against rotationin lower cylindrical cavity 112 in a manner that N-S axis 130 extendsfrom the sidewall 126′ to the sidewall 126″. As a result, sidewalls126′, 126″ are magnetized in accordance with the active magnetic polenext to it. That is, sidewall 126′ is magnetized as a N-pole whereassidewall 126″ becomes a S-pole. In contrast, because upper magnet 118 isfree to rotate about axis 122, in absence of pole shoes 102′, 102″, thepolarity of sidewalls 124′, 124″ would be determined by the relativerotational position and orientation of upper magnet 118.

As stated above, upper magnet 118 is configured to be rotated from theorientation shown in FIG. 3 . In embodiments, upper magnet 118 may berotatable by 180-185 degrees to a rotational position in which itsN-pole coincides with the N-pole of lower magnet 120 and conversely theS-poles overlie each other (see FIG. 5B). When the N-S axes 128, 130 areoriented parallel, both sidewalls 124′, 126′ will be magnetized with thesame North magnetic polarity, as will the adjoining pole shoe 102′.Further, sidewalls 124″, 126″ will be magnetized with the same Southmagnetic polarity, as will be the adjoining pole shoe 102″. Thisre-orientation of upper magnet 118 will create an ‘active’ working airgap at the lower axial workpiece contact interface 132′, 132″ of poleshoes 102′, 102″, thereby enabling the creation of a low reluctance,closed magnetic circuit to be formed. In particular, the low reluctance,closed magnetic circuit originates and finishes in the magnets 118, 120,through the sidewalls 124′, 124″, 126′, 126″, the pole shoes 102′, 102″and a ferromagnetic body that is perhaps touching both the workpiececontact interfaces 132′, 132″ of pole shoes 102′, 102″. This state maybe referred in to herein as the magnetic device 100 being in an on-state(see FIG. 5B). Conversely, the state where N-S axes 128, 130 areoriented anti-parallel, a closed magnetic circuit is formed within themagnetic device 100 and may be referred to as the magnetic device 100being in an off-state (see FIG. 5A).

Upper cylindrical cavity 110 may have a smooth wall surface, and adiameter that allows upper magnet 118 to be received therein so it canrotate with minimal friction about the N-S axis 128 and preferablymaintain a minimal airgap. In embodiments, a friction reducing coatingmay be applied to upper cylindrical cavity 110. Lower cylindrical cavity112 may have a roughened wall surface and a diameter that provides aninterference fit with lower magnet 120 such that when lower magnet 120is mounted within lower cylindrical cavity 112, it maintains itsrotational orientation and is prevented from axial and rotationaldisplacement under operating conditions of magnetic device 100.Additionally or alternatively, other mechanisms can be used, such asgluing or additional cooperating form-fitting components (not shown) tosecure lower magnet 120 within lower cylindrical cavity 112.

A circular disk 134 comprised of ferromagnetic material may be arrangedat the bottom of lower cylindrical cavity 112. Circular disk 134 maysupport lower magnet 120. In embodiments, circular disk 134 may be pressfitted or otherwise secured such as to close the lower end of lowercylindrical cavity 112 to seal lower cylindrical cavity 112 and lowermagnet 120 against contamination at a working face 136 of magneticdevice 100. The ferromagnetic nature of circular disk 134 may assist incompleting the magnetic circuit by providing additional magnetisablematerial between the sidewalls 126′, 126″, so that the field of thelower magnet 120 couples exclusively with the magnetic material providedin the lower housing component 108 and pole shoes 102′, 102″ in order toform a magnetic circuit in either the on or off states. This also allowsfor magnetic device 100 to operate with greater holding force whenturned on and cancels out any holding force when turned off.

In embodiments, a support structure 138 may be located between themagnets 118, 120. Support structure 138 may support the upper magnet 118within upper cylindrical cavity 110. Additionally or alternatively,support structure 138 may facilitate maintaining a set axial distancebetween lower circular face of the upper magnet 118 and the uppercircular face of lower magnet 120. In embodiments, support structure 138may include a circular bottom plate 140 of non-magnetisable metallicmaterial, a rotation bearing 142, and a circular non-magnetic upperplate 144. In embodiments, bottom plate 140 rests on the upper face ofthe lower magnet 120 and closes the upper open end of lower cylindricalcavity 112. In embodiments, bottom plate 140 may be transition-fittedinto the open end of lower cylindrical cavity 112. Rotation bearing 142may be seated in an appropriately sized cylindrical depression (or seat)in an upper surface of bottom plate 140. The diameter of upper plate 144is such that it can rotate within the lower terminal axial end of theupper cylindrical cavity 110. That is, upper plate 144 may have adiameter similar to that of upper magnet 118 which sits with its loweraxial end face on upper plate 144. In embodiments, an upper face ofupper plate 144 may be coated with a slip promoting PTFE coating and alower face of the upper plate 144 may include a boss or axle stump (notshown). In embodiments, the axle stump may sit within the inner ringbearing part of rotation bearing 142. Additionally or alternatively, anon-magnetisable (e.g., aluminium) circular cap (not shown) may bemounted to upper housing component 106 to cover upper cylindrical cavity110.

In embodiments, support structure 138 may be replaced by a differenttype of arrangement, in which upper magnet 118 is secured against ashaft 146 while allowing free rotation thereof, by way of a retainerclip ring (not shown) secured in an annular groove (not shown) near alower end of shaft 146.

In embodiments, shaft 146 penetrates through a hole 148 in upper magnet118, so that upper magnet 118 may rotate coaxially around shaft 146. Inembodiments, shaft 146 protrudes perpendicular from a central hubportion 152 of a cap component 150, so that positioning of shaft 146 bythe installation of cap component 150 cooperates with upper magnet 118to ensure its concentric rotation within the cylindrical cavity of upperhousing component 106. In the illustrated embodiments, shaft 146 is acylindrical pin welded or otherwise fixed to cap component 150.

In embodiments, cap component 150 may be non-magnetisable and comprise arectangular plate 154 with an arcuate window 156. In embodiments,rectangular plate 154 may be machined to have a similar footprint tothat of housing components 106, 108, i.e., rectangular. The terminalopposite ends of acuate window 156 provide “hard stops” for a rotationarresting block member 158 which is fixed to upper magnet 118 so thatblock member 158 may travel within the arcuate window 156 duringrotation of upper magnet 118 when magnetic device 100 is switchingbetween configurations. In embodiments, arcuate window 156 may include alatch mechanism 160 which operates to hold an intermediate rotationalstate of upper magnet 118 between the hard stops provided by the ends ofthe arcuate window 156. Thus, upper magnet 118 may be secured atintermediate rotational positions with respect to lower magnet 120.Additionally or alternatively, latch mechanism 160 may be included inupper housing component 106 or another portion of magnetic device 100.

In one embodiment, shaft 146 is coupled to an actuator 32 which movesupper magnet 118 to various positions relative to lower magnet 120. Inthe illustrated embodiment, one or more solenoid coil body 162 surroundupper housing 106 and orient upper magnet 118 relative to lower magnet120 through one or more currents passing through solenoid coil body 162.The solenoid coil body 162 may consist of enamel coated wire windingswrapped (or otherwise placed). In embodiments, the enamel coated wiresmay be comprised of one or more conductive materials (e.g., copper,silver, gold, and/or the like).

Cap component 150 may be further configured to support/house variouselectronic control and power components associated with and required tosupply current to solenoid coil body 162 for rotating upper magnet 118as will be described below. Alternatively, the cap component 150 mayinclude contact leads for connecting to a power supply (not shown) thatsupplies current to the solenoid coil body 162. In embodiments, capcomponent 150 may be secured to upper housing component 106 using boltsor other types of fasteners.

In embodiments, a power supply (not shown) may be connected to thesolenoid coil body 162 via suitable control circuitry to supply acurrent to the solenoid coil body 162. In response to current beingsupplied to the solenoid coil body 162, the solenoid coil body 162produces a magnetic field. In embodiments, the magnetic field producedby solenoid coil body 162 is oriented in a manner to produce a torque onupper magnet 118. The torque rotates the N-S axis 128 of upper magnet118 from a first configuration (shown in FIG. 5A) to the secondconfiguration (shown in FIG. 5B). Additionally or alternatively, uppermagnet 118 may be stopped at various intermediate configurations by thelatch mechanisms 160.

In embodiments, magnets 118, 120 may have different magnetization andcoercivity properties. For example, lower magnet 120 may be comprised ofhigh coercivity permanent magnet, which cannot be easily demagnetized byan external magnetizing influence, and upper magnet 118 may be comprisedof a medium or low coercivity magnetic element. Accordingly, themagnetic field produced by solenoid coil body 162 may affect uppermagnet 118 to a greater degree than lower magnet 120.

In embodiments, solenoid coil body 162 may comprise multiple solenoidcoil bodies. For example, solenoid coil body 162 may comprise twosolenoid coil bodies that are electrically isolated from each other andextend from one corner of the upper housing component 106, diagonallyacross a top face of upper housing component 106 to the opposing cornerof upper housing component 106 and underneath upper housing component106 to complete a winding. The respective coils may be wrapped onopposing diagonals across upper housing component 106 and cap component150, one coil being wrapped over the other, so that they form an ‘X’ ofwindings when viewed in top plan view of upper housing component 106.While the magnetic device 100 is described herein as being electricallyactuated by solenoid coil body 162, the magnetic device 100 may beactuated with an electrical actuator through a mechanical connection,such as a motor, a pneumatic actuator, a hydraulic actuator, or a manualactuator, in embodiments.

As illustrated, threaded bores 164 may be cut into the sidewalls 124′,124″, 126′, 126″. Threaded bores 164 may facilitate securing pole shoes102′, 102″ to housing components 106, 108 via fastening screws or bolts(not shown). That is, fastening screws or bolts may be inserted throughcountersunk through bores 166 of pole shoes 102′, 102″, whose spacingequals that of threaded bores 164. Both housing components 106, 108 maythus be connected to pole shoes 102′, 102″ in a way that provides asubstantially gap-free, low reluctance magnetic circuit path betweenmagnets 118, 120, sidewalls 124′, 124″, 126′, 126″, and pole shoes 102′,102″.

Pole shoes 102′, 102″ provide a ferromagnetic workpiece contactinterface for the magnetic device 100. In embodiments, pole shoes 102′,102″ may be comprised of a low magnetic reluctance ferromagneticmaterial. While pole shoes 102′, 102″ are depicted as having aparallelepiped, plate-like shape, pole shoes 102′, 102″ may have othershapes, which may be based on the shape of a workpiece to which themagnetic device 100 will attach. One example, is the cylindrical shapeshown in FIGS. 9A-9B which matches a cylindrical shape of a workpiece,such as a pipe. Another example, is the v-shape shown in FIGS. 10A-10B,which matches edges or corners of a workpiece.

As illustrated, the pole shoes 102′, 102″ include portions 168′, 168″positioned proximate to housing components 106, 108. As stated above,these portions 168′, 168″ are secured to housing components 106, 108 viaone or more fastening devices (e.g., screws, etc.). Additionally, poleshoes 102′, 102″ comprise a plurality of protrusions 170′, 170″ alsoreferred to herein as projections. The plurality of protrusions 170′,170″ respectively collectively form workpiece contact interfaces of thepole shoes 102′, 102″. In embodiments, pole shoes 102′, 102″ thatinclude the plurality of projections 170′, 170″ create a shallowermagnetic field than pole shoes having a flat workpiece contactinterface, as explained in the examples provided herein.

FIG. 6 is a side view of a portion of an exemplary pole shoe 200 whichmay serve as either pole shoe 132′ or pole shoe 132″ of magnetic device100. Pole shoe 200 comprises a first portion 202 that can be positionedproximate the housing (e.g., the housing 104) of a magnetic device(e.g., the magnetic device 100). Pole shoe 200 may also include bores204 extending through pole shoe 200 to releasably secure pole shoe 200to a housing of a magnetic device via a fastening mechanism (e.g.,fastening screws, etc.). Furthermore, pole shoe 200 includes a pluralityof projections 206 arranged on a bottom portion 208 of pole shoe 200.Each of projections 206 are separated by recess portions 210.Additionally, the plurality of projections 206 collectively form aworkpiece contact interface 212 of pole shoe 200.

As stated above, due to the plurality of projections 206 included inpole shoe 200, a magnetic device including pole shoe 200 produces astronger magnetic field near workpiece contact interface 212 than amagnetic device including a pole shoe having a flush continuous lowerprofile. The magnetic field produced near workpiece contact interface212 may be referred to herein as the shallow magnetic field.Furthermore, by including the plurality of projections 206 on pole shoe200, a magnetic device including pole shoe 200 produces a weakermagnetic field farther away in depth from pole shoe 200 than a magneticdevice including a pole shoe with a flush continuous lower profile. Themagnetic field produced farther away from the pole shoe 200 may bereferred to herein as a far-field or deep magnetic field produced bypole shoe 200. Stated another way, a magnetic device including pole shoe200 having projections 206 has a stronger holding force near workpiececontact interface 212 than a magnetic device including a pole shoe witha flush continuous interface that doesn't include projections 206.

In embodiments, the shallow magnetic field and the far-field magneticfield of a pole shoe 200 may be dependent on the type of pole shoe 200.In particular, the shallow magnetic field may be the magnetic fieldproduced from the workpiece contact interface 212 to a distance from theworkpiece contact interface 212 that is approximately equal to the width214 of the projections 206. For example, if the widths 214 of theprojections 206 are 2 mm, then the shallow magnetic field is themagnetic field produced from the workpiece contact interface 212 to a 2mm depth from the workpiece contact interface 212. Furthermore, thefar-field magnetic field produced in this example is the magnetic fieldproduced at a depth greater than 2 mm from the workpiece contactinterface 212.

As a result of a magnetic device 100 producing a stronger shallowmagnetic field and a weaker far-field magnetic field because of theprojections 206 of pole shoe 200, the magnetic device 100 may be used tode-stack thin ferromagnetic bodies better than a magnetic device 100having pole shoe without the projections 206. That is, a magnetic device100 including a pole shoe that doesn't have the projections 206 mayproduce a stronger far-field magnetic field that will result in multiplethin ferromagnetic bodies being coupled to the magnetic device. Whentrying to obtain a single thin ferromagnetic body from a stacked arrayof thin ferromagnetic bodies, this is an undesirable result. As such,instead of using a magnetic device including pole shoe without theprojections 206 to de-stack ferromagnetic bodies, a pole shoe 200including the projections 206 may be used.

In embodiments, varying the widths 214 of the projections 206 result indifferent shallow magnetic fields produced by the same magnetic device.In embodiments, to produce a preferred shallow magnetic field for aspecific ferromagnetic body, the widths 214 of the projections 206 mayhave a width within approximately +/−25% the thickness of theferromagnetic body to be de-stacked. For example, when a magnetic deviceis de-stacking 2 mm thick ferromagnetic sheets, the widths 214 of theprojections 206 could be approximately 2 mm (e.g., 2 mm+/−25%). Inembodiments, this will produce a strong shallow magnetic field between 0mm and 2 mm depth from contact interface 212. In at least oneembodiment, however, there may be a limit for producing a preferredshallow magnetic field for some ferromagnetic bodies having thicknessesless than the limit. That is, for ferromagnetic bodies having athickness less than X mm, a preferred shallow magnetic field may beproduced by projections 206 having widths 214 that are at a lower limitof X mm but are not less than the lower limit. That is, to produce apreferred magnetic field for a ferromagnetic body having a thickness of½*X mm, the widths 214 of the projections 206 may be at the lower limitof X mm instead of +/−25% of ½*X mm. If, however, the thickness of theferromagnetic body is X mm or more, then the widths 214 mayapproximately equal (e.g., +/−25%) the thickness of the ferromagneticbody. Examples of a lower limit may be in the range of 0 mm to 2 mm.However, this is only an example and not meant to be limiting.

In at least one embodiment, when a magnetic device including a pole shoe200 is coupling to ferromagnetic bodies having different thicknesses, apole shoe 200 having widths 214 that is an average of the thickness ofthe ferromagnetic bodies may be used to reduce the need to change poleshoes. Similar to above, however, a lower limit (e.g., 2.0 mm) may beapplied such that if the average thickness of the ferromagnetic bodiesis below the lower limit (i.e., <2.0 mm), the widths 214 may beconfigured to be the lower limit (i.e., 2.0 mm).

In embodiments, varying the depths 216 and/or widths 218 of the recesses210 result in different shallow magnetic fields produced by the samemagnetic device 100. In embodiments, to produce an appropriate shallowmagnetic field for a specific ferromagnetic body, the depths 216 and/orwidths 218 of the recesses 210 could be approximately the same (e.g.,+/−25%) as the widths 214 of the projections 206. For example, if thewidths 214 of the projections 206 are 2 mm, then the depths 216 and/orwidths 218 of the recesses 210 could be approximately 2 mm (e.g., 2mm+/−25%). In embodiments, this will produce a strong shallow magneticfield between 0 mm and 2 mm depth from contact interface 212. Similar toabove, however, there may be a limit for producing a preferred shallowmagnetic field for some ferromagnetic bodies having thicknesses lessthan the limit. That is, for ferromagnetic bodies having a thicknessless than X mm, a preferred shallow magnetic field may be produced bydepths 216 and widths 218 that are at a lower limit of X mm but are notless than the lower limit. That is, to produce a preferred magneticfield for a ferromagnetic body having a thickness of ½*X mm, the depths216 and widths 218 may be at the lower limit of X mm instead of +/−25%of ½*X mm. If, however, the thickness of the ferromagnetic body is X mmor more, then the depths 216 and widths 218 may approximately equal(e.g., +/−25%) the thickness of the ferromagnetic body.

Similar to above, when a magnetic device 100 including pole shoe 200 iscoupling ferromagnetic bodies having different thicknesses, a pole shoe200 having depths 216 and/or widths 218 of recesses 210 that is anaverage of the thickness of the ferromagnetic bodies may be used toreduce the need to change pole shoes. Moreover, a lower limit (e.g., 2.0mm) may be applied such that if the average thickness of theferromagnetic bodies is below the lower limit (i.e., <2.0 mm), thedepths 216 and widths 218 may be configured to be the lower limit (i.e.,2.0 mm).

As set forth above, pole shoe 200 may be releasably coupled to a housingof a magnetic device. Therefore, when projections 206 of the pole shoe200 do not have the appropriate widths 214, depths 216 and/or widths 218for the ferromagnetic body to which magnetic device 100 is coupling,pole shoe 200 may be replaced by a more appropriate pole shoe 200.

FIGS. 7A is a side view of a portion of another exemplary pole shoe 300which may serve as either pole shoe 132′ or pole shoe 132″ of magneticdevice 100 and FIG. 7B illustrates a detail view of a portion of theexemplary pole shoe depicted in FIG. 7A. Similar to pole shoe 200depicted in FIG. 6 , pole shoe 300 comprises a first portion 302 thatcan be positioned proximate to a housing (e.g., the housing 104) of amagnetic device (e.g., the magnetic device 100). Pole shoe 300 may alsoinclude bores 304 extending through pole shoe 300 to releasably securepole shoe 300 to housing 104 of magnetic device 100 via a fasteningmechanism (e.g., fastening screws, etc.). Furthermore, pole shoe 300includes a plurality of projections 306 arranged on a bottom portion 308of the pole shoe 300. Each of projections 306 are separated by a recessportion 310. The plurality of projections 306 collectively form aworkpiece contact interface 312 of pole shoe 300.

Similar to above, varying the widths 314 of the projections 306 and/orthe depths 316, and/or widths 318 of the recesses 310 result indifferent shallow magnetic fields produced by the same magnetic device100. In embodiments, to produce an appropriate shallow magnetic fieldfor a specific ferromagnetic body, the widths 314 of the projectionsand/or the depths 316, and/or widths 318 of the recesses 310 could beapproximately the same (e.g., +/−25%) as the thickness of theferromagnetic body to be coupled to magnetic device 100. In at least oneembodiment, however, there may be a limit for producing a preferredshallow magnetic field for some ferromagnetic bodies having thicknessesless than the limit. That is, for ferromagnetic bodies having athickness less than X mm, a preferred shallow magnetic field may beproduced by widths 314, depths 316, and/or widths 318 that are at alower limit of X mm but are not less than the lower limit. That is, toproduce a preferred magnetic field for a ferromagnetic body having athickness of ½*X mm, the widths 314, depths 316, and/or widths 318 maybe at the lower limit of X mm instead of +/−25% of ½*X mm. If, however,the thickness of the ferromagnetic body is X mm or more, then the widths314, depths 316, and/or widths 318 may approximately equal (e.g.,+/−25%) the thickness of the ferromagnetic body. Examples of a lowerlimit may be in the range of 0 mm to 2 mm. However, this is only anexample and not meant to be limiting.

Alternatively, when a magnetic device including the pole shoe 300 iscoupling to ferromagnetic bodies having different thicknesses, a poleshoe 300 having widths 314, depths 316, and/or widths 318 that is aboutan average of the thickness of the ferromagnetic bodies may be used toreduce the need to change pole shoes. Similar to above, however, a lowerlimit (e.g., 2.0 mm) may be applied such that if the average thicknessof the ferromagnetic bodies is below the lower limit (i.e., <2.0 mm),the widths 314, depths 316, and/or widths 318 may be configured to bethe lower limit (i.e., 2.0 mm).

In embodiments, upper portions 319 of pole shoe 300 have a continuousslope profile (the slope is defined at all points, no sharp corners).Illustratively, the upper corners 319 of pole shoe 300 may have arounded shoulder portion 320. A magnetic device 100 including a poleshoe 300 having a rounded shoulder 320 has been shown to have a highermagnetic flux transfer to a ferromagnetic body than a magnetic devicehaving a pole shoe with sharp corners. Accordingly, in at least oneembodiment, the upper corners 319 of the pole shoe 300 include roundedshoulder portions 320. In one example, the radius of curvature 322 ofthe rounded shoulder portion 320 may preferably range from 1%-75% of theheight 323 of the pole shoe 300. In another example, the radius ofcurvature 322 may preferably range from 25%-75% of the height 323 of thepole shoe 300. In a further example, the radius of curvature 322 maypreferably be in the range of 40%-60% of the height 323 of the pole shoe300.

Referring to FIG. 7B, additionally or alternatively, the recess portions310 between the projections 306 may have a continuous slope profile (theslope is defined at all points, no sharp corners) at their upperextremes. Similar to having a rounded shoulder 320, magnetic deviceincluding a pole shoe 300 having a curved recess portions 310 may have ahigher magnetic flux transfer to a ferromagnetic body than a magneticdevice including a pole shoe that includes recessed portions with sharpcorners. In embodiments, to provide a high magnetic flux transfer, theradius of curvature 324 of the curved recess portions 310 may beapproximately ½ the width 318 of the recesses 310. Test data hasindicated an improvement greater than 3% may be obtained by including aslope profile of the recess portions 310 that is ½ the width 318 of therecesses 324.

FIG. 8 is a side view of a portion of another exemplary pole shoe 400which may serve as either pole shoe 132′ or pole shoe 132″ of magneticdevice 100. Similar to pole shoes 200, 300 depicted in FIGS. 6 and7A-7B, respectively, pole shoe 400 comprises a first portion 402 thatcan be positioned proximate a housing (e.g., the housing 104) of amagnetic device (e.g., the magnetic device 100). Pole shoe 400 may alsoinclude bores 404 extending through pole shoe 400 to releasably securepole shoe 400 to a housing of a magnetic device via a fasteningmechanism (e.g., fastening screws, etc.). Furthermore, pole shoe 400includes a plurality of projections 406 arranged on a bottom portion 408of pole shoe 400. Each of the projections 406 are separated by recessportions 410. The plurality of projections 406 collectively form aworkpiece contact interface 412 of pole shoe 400.

Similar to above, varying the widths 414 of the projections 406 and/orthe depths 416, and/or widths 418 of the recesses 410 result indifferent shallow magnetic fields produced by the same magnetic device100. In embodiments, to produce an appropriate shallow magnetic fieldfor a specific ferromagnetic body, the widths 414 of the projections 406and/or the depths 416, and/or widths 418 of the recesses 410 could beapproximately the same (e.g., +/−25%) as the thickness of theferromagnetic body.

In at least one embodiment, however, there may be a limit for producinga preferred shallow magnetic field for some ferromagnetic bodies havingthicknesses less than the limit. That is, for ferromagnetic bodieshaving a thickness less than X mm, a preferred shallow magnetic fieldmay be produced by widths 414, depths 416, and/or widths 418 that are ata lower limit of X mm but are not less than the lower limit. That is, toproduce a preferred magnetic field for a ferromagnetic body having athickness of ½*X mm, the widths 414, depths 416, and/or widths 418 maybe at the lower limit of X mm instead of +/−25% of ½*X mm. If, however,the thickness of the ferromagnetic body is X mm or more, then the widths414, depths 416, and/or widths 418 may approximately equal (e.g.,+/−25%) the thickness of the ferromagnetic body. Examples of a lowerlimit may be in the range of 0 mm to 2 mm. However, this is only anexample and not meant to be limiting.

Alternatively, when a magnetic device including pole shoe 400 iscoupling to ferromagnetic bodies having different thicknesses, a poleshoe 400 having widths 414, depths 416, and/or widths 418 that is anaverage of the thickness of the ferromagnetic bodies may be used toreduce the need to change pole shoes. Similar to above, however, a lowerlimit (e.g., 2.0 mm) may be applied such that if the average thicknessof the ferromagnetic bodies is below the lower limit (i.e., <2.0 mm),the widths 414, depths 416, and/or widths 418 may be configured to bethe lower limit (i.e., 2.0 mm).

In embodiments, pole shoe 400 may also include compressible members 420arranged between projections 406 in the recessed portions 410. Inembodiments, the compressible members 420 compresses when magneticdevice 100 including the pole shoe 400 couples to a ferromagnetic body.Due to the compression of compressible members 420, static frictionbetween compressible members 420 and the ferromagnetic body is createdthat is potentially greater than the static friction between theprojections 406 and the ferromagnetic body. As such, a ferromagneticbody coupled to a magnetic device 100 including the pole shoe 400 may beless like to rotate and translate than if the ferromagnetic body wascoupled to a pole shoe that didn't include the compressible members 420.In embodiments, compressible members 420 may be comprised of an elasticmaterial such as polymers of isoprene, polyurethane, nitrile rubberand/or the like.

FIGS. 9A-9B depict another exemplary pole plate 500 which can be used aseither pole shoe 132′ or pole shoe 132″ of magnetic device 100. Similarto the pole plates 200, 300, 400 depicted in FIGS. 6, 7A-7B, and 8 ,pole plate 500 includes a plurality of projections 502 arranged on abottom portion 504 of pole plate 500. Each of projections 502 areseparated by recess portions 506. The plurality of projections 502collectively form a workpiece contact interface 508 of the pole plate500.

As illustrated, the workpiece contact interface 508 is non-planar. Inembodiments, the non-planar workpiece contact interface 508 mayfacilitate coupling a magnetic coupling device 100 to a ferromagneticworkpiece having a non-planar surface. For example, a magnetic couplingdevice 100 including pole plate 500 may be used for coupling magneticcoupling device 100 to one or more types of rods, shafts, etc. (e.g., acam shaft). While the workpiece contact interface 508 includes a curvedsurface 510, the workpiece contact interface 508 may have any other typeof non-planar surface. For example, the workpiece contact interface 508may include a similar contour as a ferromagnetic piece to which themagnetic coupling device including the workpiece contact interfaces 508is intended to couple.

Despite having a non-planar workpiece contact interface 508, varying thewidths 512 of the projections 502 and/or the depths 514, and/or widths516 of the recesses 506 result in different shallow magnetic fieldsproduced by the same magnetic coupling device. In embodiments, toproduce an appropriate shallow magnetic field for a specificferromagnetic workpiece, the widths 512 of the projections 552 and/orthe depths 514, and/or widths 516 of the recesses 506 could beapproximately the same (e.g., +/−25%) as the thickness of theferromagnetic workpiece. In at least one embodiment, however, there maybe a limit for producing a preferred shallow magnetic field for someferromagnetic workpieces having thicknesses less than the limit. Thatis, for ferromagnetic workpieces having a thickness less than X mm, apreferred shallow magnetic field may be produced by widths 512, depths514, and/or widths 516 that are at a lower limit of X mm but are notless than the lower limit. That is, to produce a preferred magneticfield for a ferromagnetic workpiece 102 having a thickness of ½*X mm,the widths 512, depths 514, and/or widths 516 may be at the lower limitof X mm instead of +/−25% of ½*X mm. If, however, the thickness of theferromagnetic workpiece is X mm or more, then the widths 512, depths514, and/or widths 516 may approximately equal (e.g., +/−25%) thethickness of the ferromagnetic workpiece. Examples of a lower limit maybe in the range of 0 mm to 2 mm. However, this is only an example andnot meant to be limiting.

Alternatively, when a magnetic coupling device including pole plate 500is coupling to ferromagnetic workpieces having different thicknesses, apole plate 500 having widths 512, depths 514, and/or widths 516 that isan average of the thickness of the ferromagnetic workpieces may be usedto reduce the need to change pole plates. Similar to above, however, alower limit (e.g., 2.0 mm) may be applied such that if the averagethickness of the ferromagnetic workpieces 102 is below the lower limit(i.e., <2.0 mm), the widths 512, depths 514, and/or widths 516 may beconfigured to be the lower limit (i.e., 2.0 mm).

FIGS. 10A-10B depict another exemplary pole plate 550 which can be usedas either pole shoe 132′ or pole shoe 132″ of magnetic device 100.Similar to the pole plates 200, 300, 400, 500 depicted in FIGS. 6,7A-7B, 8, 9A-9B, pole plate 550 includes a plurality of projections 552arranged on a bottom portion 554 of pole plate 550. Each of projections552 are separated by recess portions 556. The plurality of projections552 collectively form a workpiece contact interface 558 of the poleplate 550.

As illustrated, the workpiece contact interface 558 is non-planar. Inembodiments, the non-planar workpiece contact interface 558 mayfacilitate coupling a magnetic coupling device 100 to a ferromagneticworkpiece having a non-planar surface. For example, a magnetic couplingdevice including pole plate 550 may be used for coupling magneticcoupling device 100 to one or more edges, corners, etc. of aferromagnetic workpiece. While the workpiece contact interface 558includes two downwardly sloping surfaces 560 extending from a centerpoint 562, the workpiece contact interface 558 may have any other typeof non-planar surface. For example, the workpiece contact interface 558may include a similar contour as a ferromagnetic piece to which themagnetic coupling device including the workpiece contact interfaces 558is intended to couple.

Despite having a non-planar workpiece contact interface 558, varying thewidths 564 of the projections 552 and/or the depths 566, and/or widths568 of the recesses 556 result in different shallow magnetic fieldsproduced by the same magnetic coupling device. In embodiments, toproduce an appropriate shallow magnetic field for a specificferromagnetic workpiece, the widths 564 of the projections 552 and/orthe depths 566, and/or widths 568 of the recesses 556 could beapproximately the same (e.g., +/−25%) as the thickness of theferromagnetic workpiece. In at least one embodiment, however, there maybe a limit for producing a preferred shallow magnetic field for someferromagnetic workpieces having thicknesses less than the limit. Thatis, for ferromagnetic workpieces having a thickness less than X mm, apreferred shallow magnetic field may be produced by widths 564, depths566, and/or widths 568 that are at a lower limit of X mm but are notless than the lower limit. That is, to produce a preferred magneticfield for a ferromagnetic workpiece having a thickness of ½*X mm, thewidths 564, depths 566, and/or widths 568 may be at the lower limit of Xmm instead of +/−25% of ½*X mm. If, however, the thickness of theferromagnetic workpiece is X mm or more, then the widths 564, depths566, and/or widths 568 may approximately equal (e.g., +/−25%) thethickness of the ferromagnetic workpiece. Examples of a lower limit maybe in the range of 0 mm to 2 mm. However, this is only an example andnot meant to be limiting.

Alternatively, when a magnetic coupling device including pole plate 550is coupling to ferromagnetic workpieces 102 having differentthicknesses, a pole plate 550 having widths 564, depths 566, and/orwidths 568 that is an average of the thickness of the ferromagneticworkpieces may be used to reduce the need to change pole plates. Similarto above, however, a lower limit (e.g., 2.0 mm) may be applied such thatif the average thickness of the ferromagnetic workpieces is below thelower limit (i.e., <2.0 mm), the widths 564, depths 566, and/or widths568 may be configured to be the lower limit (i.e., 2.0 mm).

FIG. 11A is a front view of an exemplary switchable magnetic device 600and FIG. 11B is a side view of the switchable magnetic device 600.Magnetic device 600 includes pole shoes 602′, 602″ and a housing 604. Inembodiments, magnetic device 600 may have some or all of the samefeatures and/or functionality as the magnetic device 100 and pole shoes602′, 602″ may have some or all of the same features and/orfunctionality as pole shoes 102′, 102″. Additionally or alternatively,pole shoes 602′, 602″ may have some or all the same features as poleshoes 200, 300, 400 depicted in FIGS. 6, 7, and 8 , respectively. Forexample, pole shoes 602′, 602″ comprise a first portion 606 that can bepositioned proximate housing 604. Pole shoes 602′, 602″ may also includebores 608 extending through pole shoes 602′, 602″ to releasably securepole shoes 602′, 602″ to housing 604 via a fastening mechanism (e.g.,fastening screws, etc.). Furthermore, pole shoes 602′, 602″ includes aplurality of projections 610 arranged on a bottom portion 612 of poleshoes 602′, 602″. Each of the projections 610 are separated by a recessportion 614. The plurality of projections 610 included in pole shoe 602′collectively form a workpiece contact interface 616′ of pole shoe 602′,and the plurality of projection included in pole shoe 602″ collectivelyform a workpiece contact interface 616″ of pole show 602″.

Furthermore, varying the widths 618 of the projections 622 and/or depths620, and/or widths 622 of the recesses 614 result in different shallowmagnetic fields produced by the same magnetic device 600. Inembodiments, to produce an appropriate shallow magnetic field for aspecific ferromagnetic body, the widths 618 of the projections 622and/or the depths 620, and/or widths 622 of the recesses 614 could beapproximately the same (e.g., +/−25%) as the thickness of theferromagnetic body. In at least one embodiment, however, there may be alimit for producing a preferred shallow magnetic field for someferromagnetic bodies having thicknesses less than the limit. That is,for ferromagnetic bodies having a thickness less than X mm, a preferredshallow magnetic field may be produced by widths 618, depths 620, and/orwidths 622 that are at a lower limit of X mm but are not less than thelower limit. That is, to produce a preferred magnetic field for aferromagnetic body having a thickness of ½*X mm, the widths 618, depths620, and/or widths 622 may be at the lower limit of X mm instead of+/−25% of ½*X mm. If, however, the thickness of the ferromagnetic bodyis X mm or more, then the widths 618, depths 620, and/or widths 622 mayapproximately equal (e.g., +/−25%) the thickness of the ferromagneticbody. Examples of a lower limit may be in the range of 0 mm to 2 mm.However, this is only an example and not meant to be limiting.

Alternatively, when magnetic device 600 to is used to couple toferromagnetic bodies having different thicknesses, the widths 618 of theprojections 622 and/or the depths 620, and/or widths 622 of recesses 614that is an average of the thickness of the ferromagnetic bodies may beused to reduce the need to change pole shoes. Similar to above, however,a lower limit (e.g., 2.0 mm) may be applied such that if the averagethickness of the ferromagnetic bodies is below the lower limit (i.e.,<2.0 mm), the widths 618, depths 620, and/or widths 622 may beconfigured to be the lower limit (i.e., 2.0 mm).

While pole shoes 602′, 602″ depicted do not include rounded shoulders(e.g., the rounded shoulder 320) and/or a curved recess portions (e.g.,the curved recess portion 310), in the alternative embodiments, poleshoes 602′, 602″ may include one or both of those features. Additionallyor alternatively, while pole shoes 602′, 602″ depicted do not includecompressible members (e.g., the compressible members 420), inalternative embodiments, pole shoes 602′, 602″ may include one or bothof those features.

As illustrated, pole shoes 602′, 602″ have respective thicknesses 624′,624″. In embodiments, different thicknesses 624′, 624″ may producedifferent shallow magnetic fields and far-field magnetic fields bymagnetic device 600. That is, similar to the widths 618 of theprojections 610, thicknesses 624′, 624″ approximately the same as thethickness of a ferromagnetic body to which magnetic device 600 couplesto produces an appropriate shallow magnetic field for de-stacking theferromagnetic body. For example, when magnetic device 600 is de-stacking2 mm thick ferromagnetic sheets, the thicknesses 624′, 624″ could beapproximately 2 mm (e.g., 2 mm+/−25%). In embodiments, this will producea strong shallow magnetic field between 0 mm and 2 mm. In embodiments,pole shoes 602′, 602″ may be either comprised of 304 Stainless Steeland/or include aluminium surrounding at least a portion of pole shoes602′, 602″ to add structural integrity to the pole shoes 602′, 602″. Inembodiments, this may be particularly advantageous when pole shoes 602′,602″ have thin thicknesses 624′, 624″ (e.g., less than or equal to 5mm).

Additionally or alternatively, housing 604 may include an offset 626from the workpiece contact interfaces 616′, 616″. In embodiments, offset626 may be dependent on the magnetic field produced by magnetic device600. That is, in embodiments, offset 626 may be a percentage of theshallow magnetic field depth produced by magnetic device 600.Additionally or alternatively, the offset 626 may be a percentage of thethickness of the workpiece. For example, if magnetic device 600 isconfigured to produce a shallow magnetic field within the workpiecehaving a depth of X mm and/or couple to a workpiece that is X mm thick,then offset 626 may be a percentage (greater or less than 100%) of theX. In one example, offset 626 may preferably be in the range of 100% to700% of the depth of the shallow magnetic field. In another example,offset 626 may preferably be in the range of 200% to 600% of the depthof the shallow magnetic field. In a further example, the offset 626 maypreferably be in the range of 300% to 500% of the depth of the shallowmagnetic field. In yet another example, offset 626 may preferably be inthe range of 350% to 400% of the depth of the shallow magnetic field.

Additionally or alternatively, pole shoes 602′, 602″ may extend alongdirection 628 by distances 630, 632 beyond a front face 634 and a rearface 636 of the housing 604, respectively. Stated another way, the width637 of the pole shoes 602′, 602″ may be longer than the depth 638 of thehousing 604. By extending beyond the front and rear faces 634, 636, thecontact area between the workpiece contact interfaces 616′, 616″ and aferromagnetic body. The increased contact area of the workpiece contactinterfaces 616′, 616″ may increase the holding force and/or shear forceof the magnetic device 600. In one example, the distance 630, thedistance 632, and/or the width 637 may vary depending on theferromagnetic body that the magnetic device 600 is coupling. That is,depending on a preferably holding force for a ferromagnetic body, thedistance 630, the distance 632, and/or the width 637 may be varied toachieve the preferable holding force. As another example, the distance630, the distance 632, and/or the width 637 may be a percentage (greateror less than 100%) of the depth 638 of the housing 604. In one example,the distance 630 and/or the distance 632 may preferably be in the rangeof 25% to 75% of the depth 638 of the housing 604. In another example,the distance 630 and/or the distance 632 may preferably be in the rangeof 35% to 65% of the depth 638 of the housing 604. In yet anotherexample, the distance 630 and/or the distance 632 may preferably be inthe range of 45% to 55% of the 632 of the depth 638 of the housing 604.

The thickness 640 of the pole shoes 602′, 602″ may also be varied.Similar to increasing the width 637 of the pole shoes 602′, 602″,increasing the thickness 640 of the pole shoes 602′, 602″ increases thecontact area between the workpiece contact interfaces 616′, 616″ and aferromagnetic body. The increased contact area of the workpiece contactinterfaces 616′, 616″ may increase the holding force and/or shear forceof the magnetic device 600. Accordingly, the thickness 640 may be varieddepending on a desired holding force of the magnetic device 600. In oneexample, the thickness 640 may approximately match the thickness of aferromagnetic body that the magnetic device 600 is coupling. In anotherexample, the thickness 640 may vary in relation to the width 637. Thatis, depending on a ferromagnetic body that the magnetic device 600 iscoupling, it may be preferable to maintain a surface area of the contactinterface 616′, 616″ and, therefore, a holding force of the magneticdevice 600. As such, as the width 637 is increased, the thickness 640may decreased and vice-versa. Therefore, if a holding force and a widerpole shoe 616′, 616″ are preferable for a ferromagnetic body, thepreferred holding force may be maintained by decreasing the thickness640 and increasing the width 637.

In the embodiments provided above, any of the features of the pole shoes16, 132, 200, 300, 400, 500, 550, and 602 may be used in conjunctionwith one another. Additionally or alternatively, any of the projectionsand recesses of the pole shoes 16, 132, 200, 300, 400, 500, 550, and 602may be integrated into the housings of the magnetic devices 10, 100, 600instead of being coupled thereto.

Furthermore, as described above, when the projection widths and recessdepths/widths exceed a lower limit and the projection widths and recessdepths/widths of the pole shoes approximately match the thickness of theferromagnetic body, pole shoes having said characteristics produce thestrongest holding force for a ferromagnetic body having approximatelythe same thickness as the projection widths and recess depths/widths.

FIG. 12 is a flow diagram of a method 700 of using an exemplaryswitchable magnetic device with pole shoes. The method 700 comprisescontacting a ferromagnetic body with a first pole shoe, as representedby block 702. In embodiments, the first pole shoe may be releasablyattached to a housing of a magnetic device. Additionally, the magneticdevice may be able to establish two different magnetic circuits. Thefirst magnetic circuit may be referred to as the magnetic device beingin an on-state and the second magnetic circuit may be referred to as themagnetic device being in an off-state.

In embodiments, the first pole shoe, the housing, and the magneticdevice may have the same or similar features as the pole shoes 16, 102,200, 300, 400, 500, or 602; the housings 28, 104, 604; and the magneticdevices 10, 100, and 600, respectively, depicted above. For example, theferromagnetic body may be contacted by a workpiece contact interface ofthe first pole shoe, wherein the workpiece contact interface of thefirst pole shoe includes a plurality of projections. Additionally oralternatively, the magnetic device may comprise: a first permanentmagnet mounted within the housing that has an active N-S pole pair and asecond permanent magnet having an active N-S pole pair. In embodiments,the second permanent magnet may be rotatably mounted within the housingin a stacked relationship with the first permanent magnet, wherein thesecond permanent magnet is rotatable between a first position and asecond position. Additionally or alternatively, the magnetic device mayestablish a plurality of magnetic circuits that produce differentstrengths of magnetic circuits between the magnetic device and aferromagnetic body.

In embodiments, the method 700 comprises contacting a ferromagnetic bodywith a second pole shoe, as represented by block 704. In embodiments,the second pole shoe is attached to the same housing to which the firstpole shoe is attached. In embodiments, the magnetic device may be in thefirst configuration when the ferromagnetic body is contacted by thesecond pole shoe.

In embodiments, the method 700 comprises transitioning the magneticdevice from the off-state to an on-state, as represented by block 706.In embodiments, transitioning the magnetic device from the off-state tothe on-state may comprise actuating (e.g., rotating) the secondpermanent magnet from a first position to a second position.Additionally, when the magnetic device is in an on-state, the magneticcircuit is formed through the workpiece.

Referring to FIG. 13 , an exemplary robotic system 700 is illustrated.While a robotic system 700 is depicted in FIG. 13 , the embodimentsdescribed in relation thereto may be applied to other types of machines,(e.g., crane hoists, pick and place machines, etc.).

Robotic system 700 includes electronic controller 770. Electroniccontroller 770 includes additional logic stored in associated memory 774for execution by processor 772. A robotic movement module 702 isincluded which controls the movements of a robotic arm 704. In theillustrated embodiment, robotic arm 704 includes a first arm segment 706which is rotatable relative to a base about a vertical axis. First armsegment 706 is moveably coupled to a second arm segment 708 through afirst joint 710 whereat second arm segment 708 may be rotated relativeto first arm segment 706 in a first direction. Second arm segment 708 ismoveably coupled to a third arm segment 711 through a second joint 712whereat third arm segment 711 may be rotated relative to second armsegment 708 in a second direction. Third arm segment 711 is moveablycoupled to a fourth arm segment 714 through a third joint 716 whereatfourth arm segment 714 may be rotated relative to third arm segment 711in a third direction and a rotary joint 718 whereby an orientation offourth arm segment 714 relative to third arm segment 711 may be altered.Magnetic coupling device 10 is illustratively shown secured to the endof robotic arm 704. Magnetic coupling device 10 is used to couple aworkpiece 27 (not shown) to robotic arm 704. Although magnetic couplingdevice 10 is illustrated, any of the magnetic coupling devices describedherein and any number of the magnetic coupling devices described hereinmay be used with robotic system 700.

In one embodiment, electronic controller 770 by processor 772 executingrobotic movement module 702 moves robotic arm 704 to a first posewhereat magnetic coupling device 100 contacts the workpiece at a firstlocation. Electronic controller 770 by processor 772 executing amagnetic coupler state module 776 instructs magnetic device 10 to moveupper magnet 12 relative to lower magnet 14 to place magnetic couplingdevice 10 the on-state to couple the workpiece to robotic system 700.Electronic controller 770 by processor 772 executing robotic movementmodule 702 moves the workpiece from the first location to a second,desired, spaced apart location.

Once the workpiece is at the desired second position, electroniccontroller 770 by processor 772 executing magnetic coupler state module776 instructs magnetic device 10 to move upper magnet 12 relative tolower magnet 14 to place magnetic coupling device 10 in an off-state todecouple the workpiece from robotic system 700. Electronic controller770 then repeats the process to couple, move, and decouple anotherworkpiece.

In one embodiment, the disclosed magnetic devices include one or moresensors to determine a characteristic of the magnetic circuit presentbetween the magnetic device and the workpiece to be coupled to themagnetic device. Further details of exemplary sensor systems areprovided in U.S. Provisional Application No. 62/490,705, titled SMARTSENSE EOAMT, filed Apr. 27, 2017, the entire disclosure of which isexpressly incorporated by reference herein.

As stated above, other configurations of magnets may be used in place ofpermanent magnets 12, 14 or permanent magnets 130, 132. Referring toFIGS. 14 and 15 , a side sectional view of an exemplary magneticcoupling device 800 of the present disclosure is represented. Magneticcoupling device 800 includes an upper assembly 802 and a lower assembly804. Each of assemblies 802 and 804 include a plurality of spaced-apartpermanent magnets 806 and a plurality of pole portions 808. Each of theplurality of spaced-apart permanent magnets 806 are illustratively shownas a single permanent magnet but may comprise multiple permanent magnetsand/or at least one permanent magnet positioned within a housing.

Each permanent magnet 806 has a north-pole side (N) and a south-poleside (S). The permanent magnets 806 and pole portions 808 of upperassembly 802 and lower assembly 804 are each arranged in a linear arraywherein one of pole portions 808 is positioned between two of permanentmagnets 806. Further, the permanent magnets 806 are arranged so thateach of the two permanent magnets 806 contacting the pole portion 808therebetween have either their north pole sides (N) or their south polesides (S) contacting the pole portion 808. When the north-pole sides (N)of the adjacent permanent magnets 806 are contacting a pole portion 808,the pole portion 808 is referred to as a north-pole portion. When thesouth-pole sides (S) of the adjacent permanent magnets 806 arecontacting a pole portion 808, the pole portion 808 is referred to as asouth-pole portion.

In embodiments, lower assembly 804 replaces permanent magnet 14 ofmagnetic coupling device 10 or permanent magnet 130 of magnetic couplingdevice 100 and is held stationary relative to housing 28 and upperassembly 802 replaces permanent magnet 12 of magnetic coupling device 10or permanent magnet 132 of magnetic coupling device 100. Upper assembly802 is translatable relative to lower assembly 804 in directions 810 and812 to alter an alignment of the permanent magnets 806 and pole portions808 of upper assembly 802 relative to the permanent magnets 806 and poleportions 808 of lower assembly 804. Permanent magnets 806 of lowerassembly 804 are spaced apart from a workpiece 27′ due to pole portions814 of the magnet coupling device 800. Additionally, a spacer (notshown) is provided between the permanent magnets of upper assembly 802and lower assembly 804.

Magnetic coupling device 800 is in an on state when the south-poleportions 808 of lower assembly 804 are aligned with the south-poleportions 808 of upper assembly 802 and the north-pole portions 808 oflower assembly 804 are aligned with the north-pole portions 808 of upperassembly 802 (see FIG. 14 ). In the on-state, the workpiece 27′ is heldby the magnetic coupling device 800 due to a completion of a magneticcircuit from the aligned north-pole portions 808 of upper assembly 802and lower assembly 804, through the workpiece 27′, and to the alignedsouth-pole portions 808 of upper assembly and lower assembly 804, asillustrated by the magnetic flux lines 816. The size and shape of poleportions 814 result in the first magnetic circuit being substantiallyconfined to workpiece sheet 27′ of workpiece sheets 27 and of sufficientholding force to vertically lift workpiece sheet 27′ in direction 818relative to the remainder of workpiece sheets 27. Thus, magneticcoupling device 800 may function to de-stack workpiece sheets 27. Insome embodiments, a portion of the magnetic flux provided to workpiecesheets 27 by magnetic coupling device 800 may enter lower sheet 27″ ofworkpiece sheets 27, but not to a level that results in lower sheet 27″being lifted by magnetic coupling device 800 along with workpiece sheet27′. Thus, as used herein, the first magnetic circuit beingsubstantially confined to workpiece sheet 27′ of workpiece sheets 27means that the amount, if any, of the magnetic flux from switchablemagnetic lifting device 800 entering lower sheet 27″ is below a levelthat would result in the lower sheet 27″ being vertically lifted indirection 818 by magnetic coupling device 800 along with workpiece sheet27′.

Magnetic coupling device 800 is in an off state when the south-poleportions 808 of lower assembly 804 are aligned with the north-poleportions 808 of upper assembly 802 and the north-pole portions 808 oflower assembly 804 are aligned with the south-pole portions 808 of upperassembly 802 (see FIG. 15 ). In the off state, a workpiece 27′ is notheld by magnetic coupling device 800 due to a completion of a magneticcircuit within upper assembly 802 and lower assembly 804 from thealigned north-pole portions 808 of upper assembly 802 to the south-poleportions 808 of lower assembly 804 and from the aligned north-poleportions of upper assembly 802 to the south-pole portions 808 of lowerassembly 804.

In embodiments, the pole portions 808 may also have the same or similarcharacteristics as pole shoes 102, 200, 300, 400, 500, 602 (e.g., thesame or similar: widths, widths and/or depths of the recesses, roundedshoulder portions, a curved workpiece interface, a compressible memberbetween each of the pole portions 808, etc.).

Referring to FIGS. 16-18 , another exemplary magnetic assembly 900 ofthe present disclosure is represented. Magnetic assembly 900 includes anupper platter 912 and a lower platter 914. Each of platters 912 and 914include a plurality of spaced-apart permanent magnets 930 and aplurality of pole portions 950. Each of the plurality of spaced-apartpermanent magnets 930 are illustratively shown as a single permanentmagnet but may comprise multiple permanent magnets and/or at least onepermanent magnet positioned within a housing. Exemplary platters areprovided in U.S. Pat. No. 7,161,451 and U.S. Provisional PatentApplication No. 62/248,804, filed Oct. 30, 2015, titled MAGNETICCOUPLING DEVICE WITH A ROTARY ACTUATION SYSTEM, docket MTI-0007-01-US-E.

Returning to the example of FIGS. 16-18 , each permanent magnet 930 hasa north-pole side 932 and a south-pole side 934. The permanent magnets930 and pole portions 950 of platter 912 and of platter 914 are eacharranged to form a closed shape wherein one of pole portions 950 ispositioned between two of permanent magnets 930. Further, the permanentmagnets 930 are arranged so that each of the two permanent magnets 930contacting the pole portion 950 therebetween have either theirnorth-pole sides or their south-pole sides contacting the pole portion950. When the north-pole sides of the adjacent permanent magnets 930 arecontacting a pole portion 950, the pole portion 950 is referred to as anorth-pole portion. When the south-pole sides of the adjacent permanentmagnets 930 are contacting a pole portion 950, the pole portion 950 isreferred to as a south-pole portion.

Each of upper platter 912 and lower platter 914 includes an equal andeven number of permanent magnet sections and an equal number of poleportions 950. In one embodiment, in each of upper platter 912 and lowerplatter 914, permanent magnets 930 and pole portions 950 are arranged ina circular configuration.

In embodiments, lower platter 914 replaces permanent magnet 14 ofmagnetic coupling device 10 or permanent magnet 130 of magnetic couplingdevice 100 and is held stationary relative to housing 28 and upperplatter 912 replaces permanent magnet 12 of magnetic coupling device 10or permanent magnet 132 of magnetic coupling device 100 and rotatesrelative to lower platter 914. Additionally or alternatively, lowerplatter may be incorporated into the magnetic coupling device 1000described below in relation to FIGS. 19-22 .

Upper platter 912 is rotatable in directions 990, 992 about a centralaxis 994 relative to lower platter 914 to alter an alignment of thepermanent magnets 930 and pole portions 950 of upper platter 912relative to the permanent magnets 930 and pole portions 950 of lowerplatter 914.

Magnetic coupling device 900 is in an on state when the south-poleportions 950 of lower platter 914 are aligned with the south-poleportions 950 of upper platter 912 and the north-pole portions 950 oflower platter 914 are aligned with the north-pole portions 950 of upperplatter 912. In the on-state, workpiece 27 is held by magnetic couplingdevice 10 due to a completion of a magnetic circuit from the alignednorth-pole portions 950 of upper platter 912 and lower platter 914,through the workpiece 27, and to the aligned south-pole portions 950 ofupper platter 912 and 914.

Magnetic coupling device 10 is in an off state when the south-poleportions 950 of lower platter 914 are aligned with the north-poleportions 950 of upper platter 912 and the north-pole portions 950 oflower platter 914 are aligned with the south-pole portions 950 of upperplatter 912. In the off state, a workpiece 27 is not held by magneticcoupling device 10 due to a completion of a magnetic circuit withinupper platter 912 and lower platter 914 from the aligned north-poleportions 950 of upper platter 912 to the south-pole portions 950 oflower platter 914 and from the aligned north-pole portions of upperplatter 912 to the south-pole portions 950 of lower platter 914.

Referring to FIG. 16 , upper platter 912 is shown exploded relative tolower platter lower platter 914. Lower platter 914 is generallyidentical to upper platter 912. Upper platter 912 may be rotatedrelative to lower platter 914 to place magnetic coupling device 10 in anon state or an off state.

Referring to FIG. 17 , upper platter 912 is illustrated. Upper platter912 includes a cylindrical base component 920 having a central aperture922 and a plurality of radially extending apertures 924. Each of theradially extending apertures 924 is sized and shaped to receive apermanent magnet 930. Each permanent magnet 930 has a north side 932, asouth side 934, a radially inward facing side 936, a radially outwardfacing side 938, a top 940, and a bottom.

Referring to FIG. 18 , a top view of upper platter 912 is shown.Cylindrical base component 920 surrounds each of north sides 932, southsides 934, radially inward facing side 936, and radially outward facingside 938 of permanent magnet 930. In one embodiment, apertures 924 arenot through apertures, but rather blind depth apertures from the bottomside of cylindrical base component 920 and hence cylindrical basecomponent 920 would also surround top 940 of pole portions 950. In theillustrated embodiment, cylindrical base component 920 is a singleintegral component. In one embodiment, cylindrical base component 920 iscomprised of two or more components joined together.

As shown in FIG. 18 , permanent magnets 930 are arranged so that thenorth sides 932 of adjacent magnets are facing each other and the southsides 934 of adjacent magnets 930 are facing each other. Thisarrangement results in the portions 950 of cylindrical base component920 between permanent magnet 930 to act as pole extensions for permanentmagnet 930. In embodiments, base component 920 and hence pole portions950 are made of steel. Other suitable ferromagnetic materials may beused for base component 920.

Referring to FIGS. 19-22 , another exemplary magnetic coupling device1000 of the present disclosure is represented. In FIG. 19 , an explodedview of the magnetic coupling device 1000 is shown. Magnetic couplingdevice 1000 includes the magnetic assembly 900 depicted in FIGS. 16-18with the addition of a spacer 1002 arranged between the permanentmagnets of upper platter 912 and lower platter 914. Magnetic couplingdevice 1000 comprises a non-ferromagnetic housing 1004 illustrativelyhaving a circular foot print. A circular bore 1006 extends axially fromthe bottom to the top of housing 1004. The upper platter 912 and lowerplatter 914 are received in bore 1006.

The exemplary magnetic coupling device 1000 includes an actuatorassembly 1008 to facilitate rotation of the upper platter 912 relativeto the lower platter 914. In the illustrated example, the actuatorassembly 1008 includes a shaft 1010 that protrudes from a central bore1012 of the cylindrical base component 920 of the upper platter 912 intoa central bore 1014 of a rotary actuator 1016 of the actuator assembly1008. The rotary actuator 1016 is coupled to the cylindrical basecomponent 920 by pins 1018. As such, when the rotary actuator 1016 isrotated, the rotation of the rotary actuator 1016 is translated to thecylindrical base component 920 by the pins 1018 and results in rotationof the upper platter 912 relative to the lower platter 914. The shaft1010 facilitates concentric rotation of the rotary actuator 1016 and thesecond platter 912 about a central axis 1020.

The actuator assembly 1008 may include an annulus 1022 that facilitatesconcentric rotation of the rotary actuator 1016 about the central axis1020. The annulus 1022 fits within a cap component 1024. The annulus1022 may form a clearance fit with an internal surface of the capcomponent 1024 to facilitate rotation of the annulus 1022 within the capcomponent 1024. The annulus 1022 also includes a central bore 1026 thatfits over a portion 1028 of the rotary actuator 1016. The annulus 1022may be coupled to the rotary actuator 1016 via pins 1030. Alternatively,the annulus 1022 may rotate freely relative to the rotary actuator 1016.

Rotation of the rotary actuator 1016 may be accomplished by a torqueoutput shaft (not shown) being inserted into and through a central bore1031 of the cap component 1024 and received by the central bore 1014 ofthe rotary actuator 1016. The end of the torque output shaft engagesinternal ridges (not shown) of the central bore 1014 so that concentricrotation of the torque output shaft translates into concentric rotationof the rotary actuator 1016. As stated above, the rotary actuator 1016is coupled to the base component 920 by pins 1018. As such, when therotary actuator 1016 is rotated by the torque output shaft, the rotationof the rotary actuator 1016 translates to rotation of the upper platter920.

As shown in FIGS. 20-22 , the base component 920 is separated into aplurality of sectors 1034 by non-ferromagnetic pieces 1036. Each sector1034 of the workpiece contact interface 1040 includes spaced-apartprojections 1038 separated by recesses 1039 (see FIG. 22 ). Asillustrated, the spaced-apart projections 1038 are located within avertical envelope 1041 defined by the central bore 1006. Thespaced-apart projections 1038 may be integrally formed as a bottomsurface of the pole portions 950 of the base component 920.Alternatively, the spaced-apart projections 1038 may be coupled to abottom surface of the pole portions 950. While the example depictedillustrates four spaced-apart projections 1038, other embodiments mayhave two or more spaced-apart projections 1038.

The spaced-apart projections 1038 collectively form a workpiece contactinterface 1040. That is, in embodiments, the spaced-apart projections1038 form the workpiece contact interface 1040 of the pole portions 950of the base component 920. As such, the spaced-apart projections 1038may also be referred to herein as pole portion workpiece interfaces1038. In embodiments, a central projection 1042 and/or thenon-ferromagnetic pieces 1036 may be included in the workpiece contactinterface 1040.

The pole portion workpiece interfaces 1038 are located at a differentradial distances 1044 from the central projection 1042 of the basecomponent 920. In embodiments, the radial distances 1044 may be amultiple of the thickness of the workpiece sheets 27. As an example, ifthe thickness of the workpiece sheets 27 is X mm, then the radialdistances 1044 may be n*X (+/−25%), where n is an integer. The poleportion workpiece interfaces 1038 may also have the same or similarcharacteristics as pole shoes 102, 200, 300, 400, 500, 602 (e.g., thesame or similar: widths, widths and/or depths of the recesses, roundedshoulder portions, a curved workpiece interface, a compressible memberbetween each of the pole portion workpiece interfaces 1038, etc.).

Due to the pole portion workpiece interfaces 1038 being spaced apart,they may have many of the same advantages as the pole shoes 16′, 16″described above. That is, they may produce a shallow magnetic fielduseful for de-stacking the workpiece sheets 27. For example, when themagnetic coupling device 1000 is in an on state, the magnetic circuitproduced by the magnetic coupling device 1000 is substantially confinedto workpiece sheet 27′ of workpiece sheets 27 and of sufficient holdingforce to vertically lift workpiece sheet 27′ in direction 1046 (of FIG.22 ) relative to the remainder of workpiece sheets 27. Thus, magneticcoupling device 1000 may function to de-stack workpiece sheets 27. Ofcourse, in some embodiments, a portion of the magnetic flux provided toworkpiece sheets 27 by switchable magnet device 10 may enter lower sheet27″ of workpiece sheets 27, but not to a level that results in lowersheet 27″ being lifted by switchable magnetic device 1000 along withworkpiece sheet 27′. Thus, as used herein, the first magnetic circuitbeing substantially confined to workpiece sheet 27′ of workpiece sheets27 means that the amount, if any, of the magnetic flux from switchablemagnetic lifting device 1000 entering lower sheet 27″ is below a levelthat would result in the lower sheet 27″ being vertically lifted indirection 1046 by switchable magnetic lifting device 1000 along withworkpiece sheet 27′.

Referring to FIGS. 23-27 , another exemplary magnetic coupling device1100 of the present disclosure is represented. Magnetic coupling device1100 includes the lower platter 14. Alternatively, the lower permanentmagnet 14 could be replaced with the upper permanent magnet 12, theupper magnet 118, the lower magnet 120, the upper platter 912, the lowerplatter 914, or bar magnets. Additionally or alternatively, the magneticcoupling 1100 may be a parallelepiped and/or have a rectangularfootprint instead of being cylindrical and/or having a circularfootprint.

A housing 1102 of the magnetic coupling device 1100 houses the lowerpermanent magnet 14 and an actuator assembly 1104. The actuator assembly1104 facilitates movement of the lower permanent magnet 14 along theaxis 1106. In particular, in the illustrated embodiment, the actuatorassembly 1104 includes a connecting rod 1108 coupling the lowerpermanent magnet 14 to a crown 1110. That is, the connecting rod 1108extends from the lower permanent magnet 14 through a central bore 1112of an intermediate element 1114 to the crown 1110. In one example, theconnecting rod 1108 and the central bore 1112 form a clearance fit. Thecrown 1110 and interior walls of the housing 1102 may also form aclearance fit. In at least some embodiments, the intermediate element1114 acts as a shorting plate, so the magnetic circuit created by themagnet 14 is primarily contained within the housing 1102.

In the exemplary embodiment depicted, the housing 1102 includes twoports 1118. Gas and/or fluid may be provided through the ports 1118 tomove the actuator assembly 1104 from a first position shown in FIG. 23to a second position shown in FIG. 24 and vice versa. In particular, byproviding gas and/or fluid through port 1118A into a housing portion1120 above the crown 1110, the gas and/or fluid exerts pressure on a topsurface 1122 of the crown 1110, thereby exerting a downward force on theactuator assembly 1104. In response, the actuator assembly 1104 movesdownward along the axis 1106 so the lower permanent magnet 14 ispositioned near the base 1127 of the housing 1102. When the permanentmagnet 14 is positioned near the base 1127 of the housing 1102, amagnetic circuit is substantially formed through the workpiece 27′ (seeFIG. 23 ), thereby allowing the workpiece sheet 27′ to be de-stackedfrom the workpiece sheets 27″, 27′″, as discussed in more detail below.

Alternatively, by providing gas and/or fluid through port 11186 and intoa housing portion 1124 below the crown 1110, the gas and/or fluid exertspressure on a bottom surface 1126 of the crown 1110, thereby providingan upward force on the actuator assembly 1104. In response, the actuatorassembly moves upward along the axis 1106 so the lower permanent magnet14 is positioned away and/or separated from the base 1127 of the housing1102. When the lower permanent magnet 14 is positioned away and/orseparated from the base 1127 of the housing 1102, a magnetic circuit issubstantially internal to the housing 1102 (see FIG. 24 ), therebyallowing the magnetic coupling device 1110 to be separated from theworkpiece sheets 27.

While the illustrated example depicts an intermediate element 1112, inalternative embodiments the magnetic coupling device 1100 may notinclude an intermediate element 1114. In these embodiments, however,more gas and/or liquid may need to be provided into the housing portion1124 to result in movement of the actuator assembly 1104 upward awayfrom the base 1127 of the housing 1102.

In alternative embodiments, the actuator assembly 1104 may be movedalong the axis 1106 using a linear actuator 1128 coupled to anengagement portion 1130 that is coupled to the actuator assembly 1104.The actuator 1128 and/or a device providing the gas and/or liquidthrough the ports 1118 may be coupled to a controller (e.g., thecontroller 34) that controls the operation and hence the position of theactuator assembly 1104. Alternatively, the linear actuator 1128 may beactuated electrically and/or manually.

As illustrated in FIG. 25 , the housing 1102 may have a circular base1132. Referring to the illustrated embodiment shown in FIG. 25 , thebase 1132A may be separated into two sectors 1134 by a non-ferromagneticpiece 1136, so there is a sufficient gap between the N-pole and theS-pole to prevent shorting of the magnetic circuit. Each sector 1134 ofthe base 1132A includes spaced-apart projections 1138 separated byrecesses 1139 (see FIG. 24 ). As illustrated, the spaced-apartprojections 1138 are located within a vertical envelope 1141 of thehousing 1102. The spaced-apart projections 1138 may be coupled to thebase 1127 of the housing 1102. The base 1132A may include two or morespaced-part projections 1138.

The spaced-apart projections 1138 collectively form a workpiece contactinterface 1140 (see FIG. 24 ) of the base 1132A. As such, thespaced-apart projections 1138 may also be referred to herein as poleportion workpiece interfaces 1138. A central projection 1142 and/or thenon-ferromagnetic piece 1136 may be included in the workpiece contactinterface 1140 of the base 1132A.

The pole portion workpiece interfaces 1138 are located at a differentradial distances 1144 from the central projection 1140. In embodiments,the radial distances 1144 may be a multiple of the thickness of theworkpiece sheets 27. As an example, if the thickness of the workpiecesheets 27 is X mm, then the radial distances 1144 may be n*X (+/−25%),where n is an integer. The pole portion workpiece interfaces 1138 mayalso have the same or similar characteristics as pole shoes 102, 200,300, 400, 500, 602 (e.g., the same or similar: widths, widths and/ordepths of the recesses, rounded shoulder portions, a curved workpieceinterface, a compressible member between each of the pole portionworkpiece interfaces 1138, etc.). While the pole portion workpieceinterfaces 1138 are depicted as being circularly, alternatively, theymay be linear.

Due to the pole portion workpiece interfaces 1138 being spaced apart,they may have many of the same advantages as the pole shoes 16′, 16″and/or the pole portion workpiece interfaces 1038 described above. Thatis, they may produce a shallow magnetic field useful for de-stacking theworkpiece sheets 27. For example, when the magnetic coupling device 1100is in an on state (see FIG. 23 ), the magnetic circuit produced by themagnetic coupling device 1100 is substantially confined to workpiecesheet 27′ of workpiece sheets 27 and of sufficient holding force tovertically lift workpiece sheet 27′ in direction 1146 (of FIG. 23 )relative to the remainder of workpiece sheets 27. Thus, magneticcoupling device 1100 may function to de-stack workpiece sheets 27. Insome embodiments, a portion of the magnetic flux provided to workpiecesheets 27 by switchable magnet device 10 may enter lower sheet 27″ ofworkpiece sheets 27, but not to a level that results in lower sheet 27″being lifted by switchable magnetic device 10 along with workpiece sheet27′. Thus, as used herein, the first magnetic circuit beingsubstantially confined to workpiece sheet 27′ of workpiece sheets 27means that the amount, if any, of the magnetic flux from switchablemagnetic lifting device 1100 entering lower sheet 27″ is below a levelthat would result in the lower sheet 27″ being vertically lifted indirection 1146 by switchable magnetic lifting device 1100 along withworkpiece sheet 27′.

As stated above, the lower permanent magnet 14 may be replaced with theupper permanent magnet 12, the upper magnet 118, the lower magnet 120,the upper platter 912, or the lower platter 914. In embodiments wherethe lower permanent magnet 14 is replaced by the upper platter 912 orthe lower platter 914, the base 1132A may be replaced by the basedepicted in FIG. 21 .

In even other embodiments, the pole portion workpiece interfaces 1138 ofthe magnetic coupled device 1100 may be replaced by the pole shoes 16′,16″, as shown in FIGS. 26 and 27 . In embodiments, the pole shoes 16′,16″ may also have the same or similar characteristics as pole shoes 102,200, 300, 400, 500, 602 (e.g., the same or similar: widths, widthsand/or depths of the recesses, rounded shoulder portions, a curvedworkpiece interface, compressible member between each of the spaced-partprojections, etc.).

Another exemplary magnetic coupling device 1200 of the presentdisclosure is represented in FIGS. 28A-30 . FIG. 28A illustrates a sidesectional view of an exemplary switchable magnetic coupling device 1200in a first, off state and FIG. 28B illustrates a front sectional view ofmagnetic coupling device 1200. FIG. 29 illustrates a front sectionalview of the magnetic coupling device of FIGS. 28A-28B in a second, onstate. FIG. 30 illustrates a front sectional view of the magneticcoupling device of FIGS. 28A-28B in a third, on state.

Magnetic coupling device 1200 may be switched between a first, off state(depicted in FIGS. 28A-28B), a second, on state (depicted in FIG. 29 ),and/or a third, on state. When magnetic coupling device 1200 is switchedto an on state, a magnetic field produced by magnetic coupling device1200 passes through one or more ferromagnetic workpieces 1202 andcouples magnetic coupling device 1200 to one or more of theferromagnetic workpieces 1202. When magnetic coupling device 1200 isswitched to an off state, magnetic field produced by magnetic couplingdevice 1200 is primarily confined within magnetic coupling device 1200and, therefore, magnetic coupling device 1200 no longer couples to oneor more of the ferromagnetic workpieces 1202. The off state and the onstates are discussed in more detail below.

Magnetic coupling device 1200 may be used as an end of arm (“EOAMT”)unit for a robotic system, such as robotic system 700 (see FIG. 13 ),but may also be used with other lifting, transporting, and/or separatingsystems for ferromagnetic workpieces 1202. Exemplary lifting andtransporting systems include robotic systems, mechanical gantries, cranehoists and additional systems which lift and/or transport ferromagneticworkpieces 1202. Additionally, magnetic coupling device 1200 may also beused as part of a stationary fixture for holding at least one part foran operation, such as welding, inspection, and other operations.

Referring to FIG. 28A, magnetic coupling device 1200 is positioned ontop of ferromagnetic workpieces 1202 and includes a workpiece contactinterface 1204 configured to contact and engage the ferromagneticworkpieces 1202. Workpiece contact interface 1204 may be a pole plate1206. In at least one embodiment, the pole plate 1206 includes aplurality of spaced-apart projections 1208 as illustrated in FIG. 28B.In other embodiments, the pole plate 1206 does not include spaced-apartprojections 1208. The spaced-apart projections 1208 may facilitateconcentrating more magnetic flux near the workpiece contact interface1204 so that when magnetic coupling device 1200 is in an on state, themagnetic flux of the magnetic coupling device 1200 primarily passesthrough the first ferromagnetic workpiece 1202′. Exemplary aspects ofthe pole plate 1206 and the projections 1208 are discussed below.

Magnetic coupling device 1200 also includes a housing 1210 that supportsa magnetic platter 1212. Magnetic platter 1212 produces the magneticfield that allows magnetic coupling device 1200 to couple toferromagnetic workpieces 1202 when the magnetic coupling device 1200 isin an on state. In at least one embodiment, magnetic platter 1212 is alaminated magnetic platter that includes a plurality of spaced-apartpermanent magnet portions 1214 and a plurality of pole portions 1216, asshown in FIG. 28B. Each of the plurality of spaced-apart permanentmagnet portions 1214 includes one or more permanent magnets. In oneembodiment, each permanent magnet portion 1214 includes a singlepermanent magnet. In another embodiment, each permanent magnet portion1214 includes a plurality of permanent magnets. Each permanent magnetportion 1214 is diametrically magnetized and has a north-pole side and asouth-pole side.

Each pole portion 1216A is positioned between two of permanent magnetportions 1214 and pole portions 1216B are arranged adjacent to onepermanent magnet portion 1214. Further, the permanent magnet portions1214 are arranged so that each of the two permanent magnet portions 1214contacting the pole portion 1216A therebetween have either their northpole sides or their south pole sides contacting the pole portion 1216A.When the north-pole sides of the adjacent permanent magnet portions 1214are contacting a pole portion 1216A, the pole portion 1216A is referredto as a north-pole portion. When the south-pole sides of the adjacentpermanent magnet portions 1214 are contacting a pole portion 1216A, thepole portion 1216A is referred to as a south-pole portion. Similarly,for pole portions 1216B, when the south-pole side of a permanent magnetportion 1214 contacts the pole portion 1216B, the pole portion 1216B isreferred to as a south-pole portion. Conversely, when the north-poleside of a permanent magnet portion 1214 contacts the pole portion 1216B,the pole portion 1216B is referred to as a north-pole portion.

In the embodiments shown, the permanent magnet portions 1214 arearranged along a horizontal axis 1218. However, in other embodiments,the permanent magnet portions 1214 may be arranged in a circularconfiguration. Furthermore, while the embodiment illustrates magneticplatter 1212 including six permanent magnet portions 1214 and seven poleportions 1216, other embodiments may include more or fewer permanentmagnet portions 1214 and pole portions 1216. For example, in oneembodiment, magnetic platter 1212 may include one permanent magnetportion 1214 and two pole portions 1216, where one pole portion 1216 isarranged on each side of permanent magnet portion 1214.

Due to the configuration of magnetic platter 1212 and magnetic couplingdevice 1200, magnetic coupling device 1200 may be have a greatermagnetic flux transfer to one or more of the ferromagnetic pieces 1202than conventional embodiments. This results in magnetic coupling device1200 being able to lift more and/or heavier ferromagnetic workpieces1202 per magnetic volume included in magnetic coupling device 1200. Forexample, the magnetic coupling device 1200 may have a holding force ofgreater than or equal to 0.35 grams of ferromagnetic workpieces 1202 percubic mm of volume of the magnetic coupling device 1200. As anotherexample, the magnetic coupling device 1200 may have a holding force ofgreater than or equal to 0.8 grams of ferromagnetic workpieces 1202 percubic mm of volume of the housing 1210 of the magnetic coupling device1200.

To switch magnetic coupling device 1200 between a first, off state and asecond, on state, magnetic platter 1212 is linearly translatable alongan axis 1220 within an interior cavity 1222 of the housing 1204. Inembodiments, the axis 1220 is a vertical axis 1220. Alternatively, theaxis 1220 is an axis other than a vertical axis. The axis 1220 extendsbetween a first end portion 1224 of the housing 1204 and a second endportion 1226 of the housing 1210. In at least some embodiments, thefirst end portion 1224 is an upper portion of the housing 1210 and thesecond end portion 1226 is a lower portion of the housing 1210 and maybe referred to herein as such. However, in at least some otherembodiments, the first end portion 1224 is a portion of the housing 1210other than the upper portion of the housing 1210 and the second endportion 1226 is a portion of the housing 1210 other than the lowerportion of the housing 1210. When magnetic platter 1212 is arranged nearthe upper portion 1224 of the housing 1210, magnetic coupling device1200 is in a first, off state. When magnetic platter 1212 is arrangednear the lower portion 1226 of the housing 1210, magnetic couplingdevice 1200 is in a second, on state. In addition to a first, off stateand a second, on state, magnetic platter 1212 may be arranged at one ormore intermediate positions between the upper portion 1224 and the lowerportion 1226, as shown in FIG. 30 . An intermediate position may bereferred to herein as a third, on state. The third, on state may produceless magnetic flux at the workpiece contact interface 1204 than thesecond, on state, as discussed below.

To translate the magnetic platter 1212 along the vertical axis 1220 totransition to magnetic coupling device 1200 between an on state and offstate and vice-versa, magnetic coupling device 1200 includes an actuator1228. In at least one embodiment, actuator 1228 is coupled to magneticplatter 1212 via an engagement portion 1230 and a non-ferromagneticmounting plate 1232. That is, actuator 1228 is coupled to engagementportion 1230 which is coupled to the non-ferromagnetic mounting plate1232; and, non-ferromagnetic mounting plate 1232 is coupled to and incontact with magnetic platter 1212. Actuator 1228 is configured toimpart a force on engagement portion 1230 and, in response, engagementportion 1230 translates along vertical axis 1220 to transition magneticcoupling device 1200 from an off state to an on state and vice versa.That is, to transition magnetic coupling device 1200 from an off stateto an on state, actuator 1228 imparts a downward force on engagementportion 1230, which translates to non-ferromagnetic mounting plate 1232and magnetic platter 1212. In response, magnetic platter 1212 translatesfrom the upper portion 1224 to the lower portion 1226. Conversely, totransition magnetic coupling device 1200 from an on state to an offstate, actuator 1228 imparts an upward force on engagement portion 1230,which translates to non-ferromagnetic mounting plate 1232 and magneticplatter 1212. In response, magnetic platter 1212 and non-ferromagneticmounting plate 1232 translate from the lower portion 1226 to the upperportion 1224.

To arrange magnetic platter 1212 at a third, on state, actuator 1228 mayproduce a force on engagement portion 1230 to translate magnetic platter1212 from the upper portion 1224 to the lower portion 1226 or viceversa. Then, when the magnetic platter 1212 is transitioning from theupper portion 1224 to the lower portion 1226 or vice versa, a brake 1234arranged within housing 1210 and/or within actuator 1228 may engagemagnetic platter 1212, non-ferromagnetic mounting plate 1232 and/orengagement portion 1230 and stop magnetic platter 1212 at a third, onstate, as depicted in FIG. 30 .

Exemplary actuators 1228 include electrical actuators, pneumaticactuators, hydraulic actuators, and other suitable devices which imparta force on engagement portion 1230. An exemplary pneumatic linearactuator is depicted in FIG. 31 and discussed in more detail in relationthereto. An exemplary electrical actuator is an electric motor with an“unrolled” stator and rotor coupled to the engagement portion 1230.Other exemplary engagement portions and actuators are disclosed in U.S.Pat. No. 7,012,495, titled SWITCHABLE PERMANENT MAGNETIC DEVICE; U.S.Pat. No. 7,161,451, titled MODULAR PERMANENT MAGNET CHUCK; U.S. Pat. No.8,878,639, titled MAGNET ARRAYS, U.S. Provisional Patent Application No.62/248,804, filed Oct. 30, 2015, titled MAGNETIC COUPLING DEVICE WITH AROTARY ACTUATION SYSTEM, docket MTI-0007-01-US-E; and U.S. ProvisionalPatent Application No. 62/252,435, filed Nov. 7, 2015, titled MAGNETICCOUPLING DEVICE WITH A LINEAR ACTUATION SYSTEM, docket MTI-0006-01-US-E,the entire disclosures of which are herein expressly incorporated byreference.

Additionally or alternatively, actuator 1228 may include a controller1236 and/or sensor 1238A. Controller 1236 includes a processor 1240 withan associated computer readable medium, illustratively memory 1242.Memory 1242 includes control logic 1244 which when executed by processor1240 causes electronic controller 1236 to instruct actuator 1228 to movemagnetic platter 1212 so that magnetic coupling device 1200 is in an offstate, second on state and/or third on state. For example, sensor 1238Amay sense a position of actuator 1228 and, in response to apredetermined position sensed by sensor 1238A, which translates to aposition of magnetic platter 1212, control logic 1244 instructs actuator1228 to stop exerting a force on magnetic platter 1212 when magneticplatter 1212 reaches a desired position.

In at least one embodiment, actuator 1228 is a stepper motor and rotarymotion of actuator 1228 is translated to linear motion of engagementportion 1230 via a coupling (e.g., gear) between a shaft of actuator1228 and engagement portion 1230. In these embodiments, sensor 1238Acounts the pulses used to drive the stepper motor and determines aposition of the shaft of the stepper motor, which is translated to aposition of magnetic platter 1212, based on the number of pulses. Theposition of the shaft, i.e., angle, is then translated into the heightof the gap 1250. That is, magnetic platter 1212 is moved relative alongthe vertical axis 1220 to a defined position by the steps the motormoves by counting the number of pulses. In another example, a steppermotor is provided that integrates an encoder with the stepper to checkthat the proper actuation angle is maintained.

As another example, magnetic coupling device 1200 may include sensor1238B. Sensor 1238B may measure the position of magnetic platter 1212within the housing 1210. Exemplary sensors 1238B include optical sensorswhich monitor reflective strips affixed to magnetic platter 1212. Othersensor systems may be used to determine a position of magnetic platter1212.

As even another example, magnetic coupling device 1200 may include oneor more sensors 1238C (illustrated in FIG. 28B). Sensors 1238C may bemagnetic flux sensors and positioned generally at one or more positionsover pole plate 1206. Exemplary magnetic flux sensors includeHall-effect sensors. Sensors 1238C measure the leakage flux proximate toone or more north and south poles of pole plate 1206. The amount ofleakage flux at each sensor 1238C varies based on the position ofmagnetic platter 1212 relative to pole plate 1206 and based on theamount of flux passing through the north and south poles of pole plate1206, workpiece contact interface 1204 to ferromagnetic workpiece 1202.By monitoring the magnetic flux at locations opposite workpieceinterface 1204 of north and south poles of pole plate 1206, the relativeposition of magnetic platter 1212 may be determined. In embodiments,magnetic coupling device 1200 is positioned on top of ferromagneticworkpieces 1202 and the magnetic fluxes measured by sensors 1238C asmagnetic platter 1212 moves from an off state to a second, on state arerecorded as a function of position of magnetic platter 1212. Each of themagnetic fluxes are assigned to a desired position of magnetic platter1212. An exemplary sensing system having sensors 1238C is disclosed inUS patent application Ser. No. 15/964,884, titled Magnetic CouplingDevice with at Least One of a Sensor Arrangement and a DegaussCapability, filed Apr. 27, 2018, the entire disclosure of which isexpressly incorporated by reference herein.

In embodiments, the controller 1236 changes the state of magneticcoupling device 1200 in response to an input signal received from an I/Odevice 1246. Exemplary input devices include buttons, switches, levers,dials, touch displays, pneumatic valves, soft keys, and communicationmodule. Exemplary output devices include visual indicators, audioindicators, and communication module. Exemplary visual indicatorsinclude displays, lights, and other visual systems. Exemplary audioindicators include speakers and other suitable audio systems. Inembodiments, device 1200 includes simple visual status indicators, inthe form of one or more LEDs, which are driven by the processor 1240 ofcontrol logic 1244, to indicate when a predefined magnetic couplingdevice 1200 status is present or absent (e.g. Red LED on when magneticcoupling device 1200 is in a first, off state, Green LED blinking fastwhen magnetic coupling device 1200 is in a second, on state andproximity of ferromagnetic workpiece 1202 is detected, Green LED slowerblinking with Yellow LED on when contacting ferromagnetic workpiece 1202outside intended specific area on ferromagnetic workpiece 1202 (e.g.partially complete magnetic working circuit) and Yellow LED off withsteady Green LED on, showing magnetic coupling device 1200 engagementwithin threshold limits, showing safe magnetic coupling state.

For example, in one embodiment, magnetic coupling device 1200 is coupledto an end of arm of a robotic arm and I/O device 1246 is a networkinterface over which controller 1236 receives instructions from a robotcontroller on when to place magnetic coupling device 1200 in one of afirst off-state, second on-state, or third on-state. Exemplary networkinterfaces include a wired network connection and an antenna for awireless network connection. While the embodiments discussed aboverelate to electronic, pneumatic, or hydraulic actuation, in alternativeembodiments, the magnetic coupling device 1200 may be actuated manuallyby a human operator.

Magnetic coupling device 1200 may also include one or more ferromagneticpieces 1248 arranged at or near an upper portion 1224 of the housing1200, as illustrated in FIG. 28A. In at least one embodiment,non-ferromagnetic mounting plate 1232 and ferromagnetic pieces 1248 arearranged within housing 1210 so that non-ferromagnetic mounting plate1232 is located between and in contact with ferromagnetic pieces 1248when magnetic coupling device 1200 is in the first, off position.Furthermore, top portions of magnetic platter 1212 may be in contactwith bottom portions of ferromagnetic pieces 1248. In another exemplaryembodiment, the ferromagnetic pieces 1248 may extend down the sides ofthe magnetic platter 1212. In these embodiments, the ferromagneticpieces 1248 may reduce leakage of the magnetic platter 1212 by providingadditional absorption of the magnetic field generated by the magneticplatter 1212.

Non-ferromagnetic mounting plate 1232 is made of a non-ferromagneticmaterial (e.g., aluminum, austenitic stainless steels, etc.). Whenmagnetic coupling device 1200 is in a first, off state and magneticplatter 1212 and non-ferromagnetic mounting plate 1232 are positioned ator near the upper portion 1218 of the housing 1204, one or more circuitsbetween the non-ferromagnetic mounting platter 1212, ferromagneticpieces 1248 and non-ferromagnetic mounting plate 1232 is created, asillustrated in FIG. 28B. Furthermore, when magnetic coupling device 1200is in a first, off state, a gap 1250 (of FIG. 28A) that comprises airand/or another substance having a low magnetic susceptibility in theinterior cavity 1216 is between and separates pole plate 1206 andmagnetic platter 1212. As a result, little or no magnetic flux from themagnetic platter 1212 extends to the workpiece contact interface 1204and through the ferromagnetic workpieces 1202 when the magnetic couplingdevice 1200 is in the first, off state. Therefore, magnetic couplingdevice 1200 can be separated from ferromagnetic workpieces 1202.Furthermore, most if not all the magnetic flux from the magnetic platter1212 is contained within the housing 1210 due to the circuits betweenthe non-ferromagnetic mounting platter 1212, ferromagnetic pieces 1248and non-ferromagnetic mounting plate 1232.

An additional advantage of including ferromagnetic pieces 1248 is thatthe distance of the gap 1250 between the bottom of magnetic platter 1212and pole plate 1206 can be less than if magnetic coupling device 1200didn't include a non-ferromagnetic mounting plate 1232 and ferromagneticpieces 1248. That is, one or more circuits created between magneticplatter 1212, ferromagnetic pieces 1248 and non-ferromagnetic mountingplate 1232, facilitates confining most if not all the magnetic flux frommagnetic platter 1212 within the housing 1210, near the magnetic platter1212 and away from the pole plate 1206. As such, the magnetic fluxtransferred to the ferromagnetic workpieces 1202 by the magneticcoupling device 1200 is insufficient to lift one or more of theferromagnetic workpieces 1202. Stated another way, the magnetic flux maybe effectively zero at the bottom of the pole plate 1206 and, therefore,effectively no magnetic flux is transferred to the ferromagneticworkpieces 1202 by the magnetic coupling device 1202, which reduces theoverall required height the magnetic platter 1212 needs to travel (seeheight 1282 below) when the magnetic coupling device 1202 transitionsbetween an off state and one or more on states.

Conversely, if non-ferromagnetic mounting plate 1232 and ferromagneticpieces 1248 weren't included in the magnetic coupling device 1202, lessof the magnetic flux from the magnetic platter 1212 would be confinedwithin housing 1210 and/or near magnetic platter 1212. And, because lessmagnetic flux would be confined near magnetic platter 1212, the gap 1250between the bottom of magnetic platter 1212 and pole plate 1206 wouldhave to be greater in order for the magnetic flux not to extend downthrough the pole plate 1206 and couple magnetic coupling device 1200 toone or more of the ferromagnetic workpieces 1202. Due to the gap 1250being smaller in the illustrated embodiment, magnetic coupling device1200 can be smaller than other magnetic coupling devices not havingthese features.

As an example, the gap 1250 the magnetic platter 1212 may travel totransition between the first, off state to the second, on state may beless than or equal to 8 mm. Conversely, to transition from the second,on state to the first, off state, the magnetic platter 1212 may travelless than or equal to 8 mm.

Another advantage of the illustrated embodiment is that less energy canbe used by actuator 1228 to translate magnetic platter 1212 along thevertical axis 1220 within the housing 1210 due to the gap 1250 beingsmaller. Even another advantage of the illustrated embodiment, is thatit will be less likely magnetic platter 1212 will break when actuator1228 translates magnetic platter 1212 from the first, off position tothe second, on position and magnetic platter 1212 comes into contactwith pole piece 1206. This is a result of magnetic platter 1212 buildingless momentum during the transition due to the reduced gap 1250. As evenanother advantage of the illustrated embodiment, in the event magneticcoupling device 1200 fails while magnetic coupling device 1200 is in anoff state, magnetic coupling device 1200 will not transition to an onstate due to the non-ferromagnetic mounting plate 1232 and theferromagnetic pieces 1248. As such, the magnetic coupling device 1200 issafer than a magnetic coupling device that transitions from an off stateto an on state when the magnetic coupling device fails. Conversely, inthe event magnetic coupling device 1200 didn't include anon-ferromagnetic mounting plate 1232 and/or ferromagnetic pieces 1248,magnetic platter 1212 may be more likely to transition to an on statedue to the lack of magnetic circuit created in the off position.

As stated above, when the magnetic platter 1206 is positioned at or nearthe lower portion 1226 of the housing 1204, magnetic coupling device1200 is in a second, on state. As illustrated in FIG. 29 , magnetic fluxfrom the magnetic platter 1206 extends through one or more of theferromagnetic workpieces 1202 when the magnetic coupling device 1200 isin the second, on state. As such, the magnetic coupling device 1200 isconfigured to couple to one or more ferromagnetic workpieces 1202 whenthe magnetic coupling device 1200 is in the first, on state. While themagnetic flux lines are illustrated as passing through bothferromagnetic workpieces 1202′, 1202″, in some embodiments the magneticflux lines primarily pass only through the ferromagnetic workpiece1202′. When the magnetic flux lines primarily pass through the firstferromagnetic workpiece 1202′, the magnetic coupling device 1200 can beused to de-stack and separate the ferromagnetic workpieces 1202 from oneanother.

To facilitate the magnetic flux lines primarily passing through only thefirst ferromagnetic workpiece 1202′ when magnetic coupling device 1200is in a second, on state, the magnetic platter 1212 may be removable andreplaceable, which allows different strength, height, and/or widthmagnetic platters 1212 to be used with the magnetic coupling device1200. The strength, height, and/or width of the magnetic platter 1212may be selected based on the thickness of the ferromagnetic workpiece1202 so that the ferromagnetic workpieces 1202 can be adequatelyde-stacked and separated from one another when magnetic coupling device1200 is in the second, on position.

Additionally or alternatively, the pole plate 1206 may be removable andreplaceable, which allows different types of pole plates 1206 to be usedwith the magnetic coupling device 1200. For example, the pole plate 1206may be selected based on the type of ferromagnetic workpiece 1202 towhich the magnetic coupling device 1200 is being coupled. For example,the magnetic coupling device 1200 may be handling class-a surfaces thatcannot be scratched or marred. As a result, a pole plate 1206 havingrubber (or another material that reduces the likelihood theferromagnetic workpiece 1202 is scratched or marred) arranged on theworkpiece contact interface may be selected and incorporated into themagnetic coupling device 1200. As another example, a pole plate 1206having different projections and/or gaps may be selected based on thethickness of the ferromagnetic workpiece 1202 to which the magneticcoupling device 1200 is being coupled. Additional examples of therelevance of the projections and/or gaps is explained in more detailabove in relation to FIGS. 6-11B.

As discussed in more detail below in relation to FIG. 31 , the housing1204 is configured in a manner that allows the magnetic platter 1212and/or the pole plate 1206 to be easily removable and replaceable.

Additionally or alternatively, magnetic coupling device 1200 may betransition to one or more intermediate states as stated above. Forexample, magnetic coupling device 1200 may transition to a third, onstate, as illustrated in FIG. 30 . The third, on state is when magneticplatter 1212 is located along the vertical axis 1220 between thelocation of the magnetic platter 1212 when the magnetic coupling device1200 is in the first, off state and the location of the magnetic platter1212 when the magnetic coupling device 1200 is in the second, on state.In embodiments where the same magnetic platter 1212 is being used, lessmagnetic flux passes through the workpiece contact interface 1204 andinto the ferromagnetic workpieces 1202 when magnetic coupling device1200 is in the third, on state than when the magnetic coupling device1200 is in the second, on state, as illustrated in FIG. 30 . That is,assuming the same strength magnetic platter 1212 is being used in theembodiments depicted in FIG. 29 and FIG. 30 , magnetic flux lines passthrough both ferromagnetic workpieces 1202′, 1202″ in FIG. 29 , whereasmagnetic flux lines pass through only ferromagnetic workpiece 1202′ inFIG. 30 . By being able to be in a third, on state, magnetic couplingdevice 1200 may be able to de-stack different thickness of ferromagneticworkpieces 1202 without having to replace magnetic platter 1212 with adifferent strength magnetic platter 1212.

As stated above, the pole plate 1206 includes a plurality of projections1208. Each of the projections 1208 acts as a pole extension for arespective pole portion of the pole portions 1216. That is, when themagnetic coupling device 1200 is in a second or third, on state, therespective north or south pole of the pole portions 1216 extends downthrough a respective projection 1208. A magnetic circuit is then createdthat goes from a N pole portion 1216 through a respective N-poleprojection 1208, through one or more ferromagnetic workpieces 1202,through a S-pole projection 1208, and through a S pole portion 1216.Each permanent magnetic portion creates one of these magnetic circuitswhen the magnetic coupling device 1200 is in an on state. As explainedin more detail above in relation to FIGS. 6-11A, the size of theprojections 1208 and the distance therebetween affect the flux transferto the ferromagnetic workpieces 1202 and allow more effectivede-stacking of ferromagnetic materials 1202 and an increased holdingforce. For example, in at least some embodiments, to achieve the highestconcentration of magnetic flux being transferred through a ferromagneticpiece 1202′ of the ferromagnetic workpieces 1202 and therefore have thegreatest likelihood of being able to de-stack the ferromagneticworkpiece 1202′ from the ferromagnetic workpieces 1202″, 1202′″, thesize of the projections (e.g., width and height) and the gaptherebetween should approximately match the thickness of theferromagnetic workpieces 1202.

To separate the N and S projections 1208, the pole plate 1206 mayinclude slots configured to receive one or more non-ferromagnetic pieces1252 (depicted in FIG. 28B). The non-ferromagnetic pieces 1252 may bearranged within respective envelopes 1254 (depicted in FIG. 28B) betweeneach of the projections 1208. Due to the non-ferromagnetic pieces 1252,the magnetic circuit created by the permanent magnet portions 1214 doesnot extend substantially through the non-ferromagnetic pieces 1252 and,therefore, the N and S projections are separated from one another.Furthermore, as stated above, the projections 1208 result in magneticflux from magnetic platter 1212 being nearer the workpiece contactinterface 1204 than if the pole plate 1206 did not include a pluralityof projections 1208. Different aspects of the projections 1208facilitating magnetic flux from magnetic platter 1212 to be concentratednearer the workpiece contact interface 104 are discussed above inrelation to FIGS. 6-11A. In alternative embodiments, the projections1208 and recesses therebetween may be integrated directly into thehousing 1210.

Referring to FIG. 31 , an exploded view of the magnetic coupling device1200 is illustrated. As illustrated, the housing 1210 includes a lowerportion 1210A releasable securable to an upper portion 1210B. The lowerportion 1210A may be secured to the upper portion 1210B using one ormore screws 1256. The screws 1256 may provide easy access to componentsof magnetic coupling device 1210 arranged within the housing 1210, asexplained below.

Prior to joining the lower portion 1210A and the upper portion 1210B,the lower portion 1210A receives a pole plate 1206. In at least oneembodiment, the lower portion 1210A includes recesses/cutouts 1258configured to receive tabs 1260 of the pole plate 1206. The tabs 1260facilitate proper positioning of the pole plate 1206 within the lowerportion 1210A. Proper positioning of the pole plate 1206 may facilitateeasy replacement of the pole plate 1206 in the event a pole plate 1206with different projections 1208 than a currently installed pole plate1206 is desired. For example, the lower portion 1210A of the housing1210 can be separated from the upper potion 1210B by removing the screws1256. Then, the pole plate 1206 can be removed from the lower portion1210A. After which, another pole plate 1206 having different projections1208 can be inserted into the lower portion 1210A so that the tabs 1260are received by the recesses/cutouts 1258. Finally, the screws can 1256be used to secure the lower portion 1210A to the upper portion 1210A.The tabs 1260 may be comprised of a ferromagnetic material.

In addition to or in alternative to replacing the pole plate 1206, thedesign of magnetic coupling device 1200 also facilitates easy removaland replacement of magnetic platter 1212. For example, as illustrated,the non-ferromagnetic mounting plate 1232 is coupled to the magneticplatter 1212 via one or more screws 1261. After removing the lowerportion 1210A from the upper portion 1210B, the magnetic platter 1212can be lowered along the vertical axis 1220 so the screws 1261 can beaccessed. Once the screws 1261 are unscrewed, the magnetic platter 1212can be separated from the non-ferromagnetic mounting plate 1232 andexchanged for another magnetic platter 1212. The new magnetic platter1212 can be secured to the non-ferromagnetic mounting plate 1232 usingthe screws 1261. After which, the lower portion 1210A and the upperportion 1210B can be coupled together using the screws 1256.

In some instances, the magnetic platter 1212 may need to be replaced inthe event the magnetic platter 1212 is broken or damaged. In otherinstances, the magnetic platter 1212 may need to be replaced with amagnetic platter 1212 that produces a stronger or weaker magnetic field.As discussed above, replacing the magnetic platter 1212 with a magneticplatter 1212 having a stronger or weaker magnetic may facilitatede-stacking the ferromagnetic workpieces 1202. For example, a firstmagnetic platter 1212 may produce enough magnetic flux through the firstand second ferromagnetic workpieces 1202′, 1202″ to lift bothferromagnetic workpieces 1202′, 1202″. However, separating the firstferromagnetic workpiece 1202′ from the second ferromagnetic workpiece1202″ may be desirable. In these instances, a second magnetic platter1212 that is weaker than the first magnetic platter 1212 and onlyproduce enough magnetic flux through the ferromagnetic workpieces 1202to lift the first ferromagnetic workpiece 1202′ may replace the firstmagnetic platter 1212.

In the illustrated embodiment, a lower portion 1228A of the actuator1228 is coupled to the housing 1210 using one or more screws 1262. Assuch, the lower portion 1228A acts as a cover to the housing 1210.Further, ferromagnetic pieces 1248 are coupled to a bottom portion 1228Aof the actuator 1228 using the one or more screws 1262. As such, whenthe magnetic platter 1212 and non-ferromagnetic mounting plate 1232 aremoved to an upper portion of the housing 1210 and magnetic couplingdevice 1200 is in the first, off position, magnetic platter 1212 isarranged in contact with the ferromagnetic pieces 1248. That is, therecontact between the outside portions of the magnetic platter 1212 andthe ferromagnetic pieces 1248, as illustrated.

Magnetic circuits are then formed from N pole portions 1216 of themagnetic platter 1212 through one of the ferromagnetic workpieces 1248,through the non-ferromagnetic mounting plate 1232, through the otherferromagnetic workpiece 1248 and to S pole portions 1216 of the magneticplatter 1212. The circuit results in a number of advantages for themagnetic coupling device 1200, which are discussed above.

As illustrated, non-ferromagnetic mounting plate 1232 is coupled to theengagement portion 1230 with a screw 1266. The engagement portion 1230includes a first portion 1230A and a second portion 1230B, wherein in atleast some embodiments, the first portion 1230A has a smallercross-sectional area than the second portion 1230B. In at least oneembodiment, the first portion 1230A extends through a conduit 1268 inthe bottom portion 1228A and coupled to the non-ferromagnetic mountingplate 1232 via the screw 1266. Due to the coupling of the engagementportion 1230 to the non-ferromagnetic mounting plate 1232, translationof the engagement portion 1230 along the vertical axis 1220 willtranslate the non-ferromagnetic mounting plate 1232 and magnetic platter1212 along the vertical axis 1220.

To translate the engagement portion 1230 along the vertical axis 1220,the actuator 1228 may be pneumatically actuated. For example, theactuator's housing 1228B may include ports 1274 including a first port1274A and a second port 1274B. When air is provided into port 1274A, viaan air compressor or otherwise, the pressure within the actuator'shousing 1228B and above the second portion 1230B increases, whichresults in the engagement portion 1230 moving downward along thevertical axis 1220. The translation of the engagement portion 1230results in the magnetic platter 1212 moving downward along the verticalaxis 1220 so the magnetic coupling device 1200 is transitioned from afirst, off state to a second, on state or a third, on state or from athird, on state to a second, on state. To confine air provided into port1274A within the actuator's housing 1228B and above engagement portion1230, actuator 1228 may include a cover (not shown) secured to theactuator's housing 1228B via one or more screws 1276. Additionally oralternatively, air may be withdrawn from port 1274B to reduce thepressure below the second portion 1230B relative to the pressure abovethe second portion 1230B, which results in the engagement portion 1230moving downward along the vertical axis 1220.

Conversely, when air is provided into the port 1274B, the pressurewithin the actuator's housing 1228B and below the second portion 1230Bincreases, which results in the plate moving upward along the verticalaxis 1220. The translation of the engagement portion 1230 results in themagnetic platter 1212 moving upward along the vertical axis 1220 so themagnetic coupling device 1200 is transitioned from a second, on state toa third, on state or a first, off state or from a third, on state to afirst, off state. Additionally or alternatively, air may be withdrawnfrom port 1274A to reduce the pressure above the second portion 1230Brelative to the pressure below the second portion 1230B, which resultsin the engagement portion 1230 moving upward along the vertical axis1220.

In at least some other embodiments, the ports 1274A, 1274B may be formedthrough the housing 1210B and pressure or a reduction in pressure may beapplied to the top of the magnetic platter 1212 or the bottom of themagnetic 1212 to translate the magnetic platter 1212 along the verticalaxis 1220.

FIGS. 32A-32B illustrate a top sectional view of the magnetic couplingdevice of FIGS. 28A-28B in different positions on a ferromagneticworkpiece 1202. Referring to FIG. 32A, the non-ferromagnetic magneticplatter 1212 is shown on ferromagnetic workpiece 1202′. As illustrated,the entirety of the footprint of the magnetic platter 1212 has beenplaced on ferromagnetic workpiece 1202′. As used herein, the termfootprint may be defined as the surface area of the magnetic platter1212, i.e., the width 1280 times the height 1282. It is preferable tohave the entire footprint of the magnetic platter 1212 to be placed onthe ferromagnetic workpiece 1202′ because the most amount of flux willbe transferred from magnetic platter 1212 to ferromagnetic workpiece1202′. When the entire footprint of the magnetic platter 1212 is placedon ferromagnetic workpiece 1202′, magnetic coupling device 1200 may beconfigured to lift greater than or equal to 22.0 grams of ferromagneticworkpieces 1202 per square mm of area of footprint of the magneticplatter 1212.

While it is preferable to have the entire footprint of the magneticplatter 1212 places on the ferromagnetic workpiece 1202′, oftentimesmagnetic platter 1212 will be placed on ferromagnetic workpiece 1202′ asshown in FIG. 32B. This can occur when magnetic coupling device 1200 isattached to an end of arm unit for a robotic system, such as roboticsystem 700 (of FIG. 13 ), where placement of magnetic platter 1212 onferromagnetic workpiece 1202′ is being performed using computer visionor some other automated process.

In the event magnetic platter 1212 is placed on ferromagnetic workpiece1202′ as shown in FIG. 32B, the configuration of magnetic platter 1212may offer some advantages. Specifically, there may be a lower likelihoodmagnetic platter 1212 will peel away from ferromagnetic workpiece 1202′when magnetic platter 1212 lifts ferromagnetic workpiece 1202′ comparedto other magnetic coupling devices. That is, due to multiple permanentmagnetic portions 1214 being included in the magnetic platter 1212, whenthe magnetic platter 1212 is placed on ferromagnetic workpiece 1202′ asshown in FIG. 32B, only the left most permanent magnetic portion 1214 isoff of ferromagnetic workpiece 1202′. Therefore, five other magneticcircuits are still formed between the magnetic platter 1212 and theferromagnetic workpiece 1202′. As such, the magnetic platter 1212 maystill be operating at approximately an 83% capacity (⅚=0.83).Comparatively, if the magnetic platter 1212 only included one permanentmagnetic portion 1214, one-third of the magnetic circuit wouldn't beformed with the ferromagnetic workpiece 1202′ due to 1⅔ of the poleportion being off the ferromagnetic workpiece 1202′. As such, magneticplatter 1212 may be operating at approximately 66% capacity.

FIG. 33 is a flow diagram of a method 1300 of using an exemplaryswitchable magnetic device with pole sectors. The method 1300 comprisescontacting a ferromagnetic body with a first pole sector, as representedby block 1302. In embodiments, the first pole sector may be attached toa base of a housing of a magnetic device. Additionally, the magneticdevice may be able to establish two different magnetic circuits. Thefirst magnetic circuit may be referred to as the magnetic device beingin an on-state and the second magnetic circuit may be referred to as themagnetic device being in an off-state.

In embodiments, the first pole sector, the housing, and the magneticdevice may have the same or similar features as the pole sectors 1034,1134; the housings 1002, 1102; and the magnetic devices 1000, 1100,respectively, depicted above. For example, the ferromagnetic body may becontacted by a workpiece contact interface of the first pole sector,wherein the workpiece contact interface of the first pole sectorincludes a plurality of projections.

The magnetic device may comprise: at least one first permanent magnetmounted within the housing that has an active N-S pole pair and at leastone second permanent magnet having an active N-S pole pair. Inembodiments, the at least one second permanent magnet may be rotatablymounted within the housing in a stacked relationship with the at leastone first permanent magnet, wherein the at least one second permanentmagnet is rotatable between a first position and a second position.Additionally or alternatively, the magnetic device may establish aplurality of magnetic circuits that produce different strengths ofmagnetic circuits between the magnetic device and a ferromagnetic body.

Alternatively, the magnetic device may comprise at least one firstpermanent magnet that is moveable relative to a base of the housing.Additionally or alternatively, the magnetic device may establish aplurality of magnetic circuits that produce different strengths ofmagnetic circuits between the magnetic device and a ferromagnetic body.In embodiments, the magnetic device may produce one magnetic circuitthat is substantially confined within its housing when the at least onefirst permanent magnet is positioned away and/or separated from the baseof the housing.

In embodiments, the method 1300 comprises contacting a ferromagneticbody with a second sector, as represented by block 1304. In embodiments,the second pole sector is attached to the same housing to which thefirst pole sector is attached. In embodiments, the magnetic device maybe in the first configuration when the ferromagnetic body is contactedby the second pole sector.

In embodiments, the method 1300 comprises transitioning the magneticdevice from the off-state to an on-state, as represented by block 1306.In embodiments, transitioning the magnetic device from the off-state tothe on-state may comprise actuating (e.g., rotating or linearlytranslating) the at least one second permanent magnet from a firstposition to a second position. Additionally, when the magnetic device isin an on-state, the magnetic circuit is formed through the workpiece.

Each of the disclosed magnetic coupling devices described above may beused in combination with a mechanical lifting apparatus that lift andtransport a ferromagnetic workpiece from a first location to a secondlocation. Exemplary mechanical lifting apparatuses include mechanicalgantries, crane hoists, stationary fixtures, robotic fixtures, etc.

Various modifications and additions can be made to the exemplaryembodiments discussed without departing from the scope of the presentinvention. For example, while the embodiments described above refer toparticular features, the scope of this invention also includesembodiments having different combinations of features and embodimentsthat do not include all of the described features. Accordingly, thescope of the present invention is intended to embrace all suchalternatives, modifications, and variations as fall within the scope ofthe claims, together with all equivalents thereof.

What is claimed is:
 1. A magnetic device for magnetically coupling to aferromagnetic body, comprising: a housing; a plurality of pole shoescoupled to the housing, wherein a first portion of the plurality of poleshoes cooperate with the housing to form a first pole of the magneticdevice and a second portion of the plurality of pole shoes cooperatewith the housing to form a second pole of the magnetic device andwherein each of the first pole of the magnetic device and the secondpole of the magnetic device includes a ferromagnetic body having a firstportion positioned proximate the housing and a second portion includinga plurality of spaced apart projections which collectively form aworkpiece contact interface of the pole; a plurality of permanentmagnets including a first permanent magnet supported by the housing andhaving an active N-S pole pair and a second permanent magnet supportedby the housing and configurable relative to the first permanent magnetto provide a first configuration wherein a north pole of the secondmagnet is aligned with a north pole of the first permanent magnet and asouth pole of the second magnet is aligned with a south pole of thefirst permanent magnet and a second configuration wherein the north poleof the second magnet is misaligned with the north pole of the firstpermanent magnet and the south pole of the second magnet is misalignedwith the south pole of the first permanent magnet; and wherein themagnetic device establishes a first magnetic circuit with the firstpermanent magnet and the second permanent magnet through the pluralityof pole shoes when the second permanent magnet is in the firstconfiguration and a second magnetic circuit with the first permanentmagnet and the second permanent magnet when the second permanent magnetis in the second configuration.
 2. The magnetic device of claim 1,wherein the first magnetic circuit substantially passes through thefirst pole and the second pole to couple the ferromagnetic body to themagnetic device and the second magnetic circuit is substantiallyconfined within at least a portion of the housing and the plurality ofpole shoes.
 3. The magnetic device of claim 1, wherein the workpiececontact interface of the first pole extends along a lower end of thefirst pole, the lower end of the first pole having a first number ofprojections of the plurality of spaced apart projections and a secondnumber of recesses interposed between the first number of projections,the second number being at least two.
 4. The magnetic device of claim 3,wherein the second number is at least three.
 5. The magnetic device ofclaim 3, wherein the second number is at least five.
 6. The magneticdevice of claim 3, wherein each of the recesses is sized to prevent theferromagnetic body from entering the respective recess.
 7. The magneticdevice of claim 3, wherein each of the recesses has a respective profileextending between the adjacent projections, the respective profilehaving a continuous slope.
 8. The magnetic device of claim 3, wherein atleast one of the recesses has a depth substantially equal to a thicknessof the ferromagnetic body to be coupled to the magnetic device.
 9. Themagnetic device of claim 3, wherein each of the recesses has a depthsubstantially equal to a thickness of the ferromagnetic body to becoupled to the magnetic device.
 10. The magnetic device of claim 3,wherein at least one of the recesses has a width substantially equal toa thickness of the ferromagnetic body to be coupled to the magneticdevice.
 11. The magnetic device of claim 3, wherein each of the recesseshas a width substantially equal to a thickness of the ferromagnetic bodyto be coupled to the magnetic device.
 12. The magnetic device of claim3, wherein at least one of the recesses has a width substantially equalto a depth of the at least one recess.
 13. The magnetic device of claim1, wherein the plurality of pole shoes are removably coupled to thehousing.
 14. The magnetic device of claim 1, wherein the first portionof the plurality of pole shoes includes a first pole shoe which includesthe plurality of spaced apart projections for the first pole and thesecond portion of the plurality of pole shoes includes a second poleshoe which includes the plurality of spaced apart projections for thesecond pole.
 15. The magnetic device of claim 14, wherein the housinghas an outer envelope having an overall envelope length of the housing,an overall envelope width of the housing, and an overall envelope heightof the housing and wherein the first pole shoe forms a south pole of themagnetic device and the second pole shoe forms a north pole of themagnetic device, the first pole shoe being positioned on a first side ofthe housing and the second pole shoe being positioned on a second sideof the housing.
 16. The magnetic device of claim 15, wherein each thesouth pole shoe and the north pole shoe have at least a portion thatextends outside each of the overall envelope length of the housing, theoverall envelope width of the housing, and the overall envelope heightof the housing.
 17. The magnetic device of claim 15, wherein each thesouth pole shoe and the north pole shoe have at least a first portionextending outside the outer envelope of the housing in a first directionand a second portion extending beyond the outer envelope of the housingin a second direction, each of the first direction and the seconddirection being along one of the overall envelope length of the housing,the overall envelope width of the housing, and the overall envelopeheight of the housing.
 18. The magnetic device of claim 15, wherein eachof the south pole and the north pole includes a single unitary poleshoe.
 19. The magnetic device of claim 15, wherein each of the firstpole shoe and the second pole shoe extend below the housing such thatthe housing is spaced apart from the ferromagnetic body when theworkpiece contact interfaces of the first pole shoe and the second poleshoe contact the ferromagnetic body.
 20. The magnetic device of claim14, further comprising a compressible member arranged between theplurality of projections of the first pole shoe and the second poleshoe.
 21. The magnetic device of any of claim 1, wherein the respectiveplurality of projections of each of the first pole and the second poleforms a non-linear workpiece contact interface.
 22. The magnetic deviceof claim 1, wherein the respective plurality of projections of each ofthe first pole and the second pole forms a linear workpiece contactinterface.
 23. The magnetic device of claim 1, wherein the secondpermanent magnet is movable relative to the first permanent magnet andthe magnetic device further comprising an actuator operatively coupledto the second permanent magnet to move the second permanent magnetrelative to the first permanent magnet to a first position correspondingto the first configuration and a second position corresponding to thesecond configuration.
 24. The magnetic device of claim 23, wherein theactuator rotates the second permanent magnet relative to the firstpermanent magnet.
 25. The magnetic device of claim 23, wherein theactuator is one of a rotary actuator and a linear actuator.
 26. Themagnetic device of claim 23, wherein the actuator is one of a hydraulicactuator, a pneumatic actuator, and an electrical actuator.
 27. Themagnetic device of claim 23, wherein the second permanent magnet ishoused in a second housing received in the housing, the second housingbeing rotatable by the actuator to rotate the second permanent magnet.28. The magnetic device of claim 1, wherein each of the first pole ofthe magnetic device and the second pole shoe of the magnetic devicecarries a compressible component positioned to be in contact with theferromagnetic body when the ferromagnetic body is coupled to themagnetic device.
 29. The magnetic device of claim 1, wherein themagnetic coupling device is carried by an end of a robotic arm.
 30. Themagnetic device of claim 1, further comprising a plurality of wiresarranged about the second permanent magnet and the second permanentmagnet is selectively placed in one of the first configuration and thesecond configuration by applying a current to the plurality of wires andthe second permanent magnet remaining in the selected one of the firstconfiguration and the second configuration when the current is removed.31. A magnetic device for magnetically coupling to a ferromagnetic body,comprising: a plurality of permanent magnets including a first permanentmagnet having an active N-S pole pair and a second permanent magnetconfigurable relative to the first permanent magnet to provide a firstconfiguration wherein a north pole of the second magnet is aligned witha north pole of the first permanent magnet and a south pole of thesecond magnet is aligned with a south pole of the first permanent magnetand a second configuration wherein the north pole of the second magnetis misaligned with the north pole of the first permanent magnet and thesouth pole of the second magnet is misaligned with the south pole of thefirst permanent magnet; an assembly supporting the plurality ofpermanent magnets and including a first plurality of spaced apartprojections which collectively form a first workpiece contact interfaceand a second plurality of spaced apart projections which collectivelyform a second workpiece contact interface housing; and wherein themagnetic device establishes a first magnetic circuit with the firstpermanent magnet and the second permanent magnet through the firstplurality of spaced apart projections and the second plurality of spacedapart projections when the second permanent magnet is in the firstconfiguration and a second magnetic circuit within the assembly with thefirst permanent magnet and the second permanent magnet when the secondpermanent magnet is in the second configuration.
 32. The magnetic deviceof claim 31, wherein the assembly includes a lower housing and an upperhousing.
 33. The magnetic device of claim 32, wherein the firstpermanent magnet is positioned in the lower housing and the secondpermanent magnet is positioned in the upper housing.
 34. The magneticdevice of claim 31, wherein the assembly includes a plurality ofdetachable pole shoes.
 35. The magnetic device of claim 31, wherein thesecond permanent magnet is movable relative to the first permanentmagnet and the magnetic device further comprising an actuatoroperatively coupled to the second permanent magnet to move the secondpermanent magnet relative to the first permanent magnet to a firstposition corresponding to the first configuration and a second positioncorresponding to the second configuration.